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FEATURES

26 COLD FIRE

In Antarctica's Dry Valleys,

the deep chambers

and conduits that poured

hot lava onto the surface

are exposed as nowhere

else on Earth. EDMOND A. MATHEZ

32 IN THE HEAT OF THE NIGHT An assassin hug's sensory journey GRACIELA FLORES

38 UNHAPPY TRAILS Forensic examination of ancient remains

sheds new light on the emergence

of Florida's Seminole Indians. CHRISTOPHER M. STOJANOWSKI

ON THE COVER: Mother African elephant and her calf mm DEPARTMENTS

4 THE NATURAL MOMENT Down the Hatch Photograph by Solvin ZankI

6 UP FRONT Editor's Notebook 46 THIS LAND 8 CONTRIBUTORS Sand Trap Robert H. Mohlenbrock 10 LETTERS 48 BOOKSHELF 12 SAMPLINGS Laurence A . Marschall News from Nature 53 nature.net 16 UNIVERSE ChiU Out Heading Out Robert Anderson Neil deGmsse Tyson COVER STORY 22 NATURALISTS AT LARGE Comeback Kids Delia and Mark Owens

55 OUT THERE Not Dead Yet Charles Liu

59 THE SKY IN JULY AND AUGUST Joe Rao

60 AT THE MUSEUM

64 ENDPAPER Messing About Dru Clarke

PICTURE CREDITS: Page 8

Visit our Web site at www.naturalhistorymag.com A "\ Has Evolution Made A Monkey Out df You?

Ape To Man \ The Rev^ution in Evolution. August 7th 9pm/8c

THE HISTORY CHANNEL History.com u X

Ul N

to DC

o O) LU

2005 4, — ——

THE NATURAL MOMENT UP FRONT

See preceding two pages reat In- Epilogue G agua, the southernmost island in the Smart. Gregarious. Long-lived. Gentle when treated well. Bahamas, hosts Dangerous when angered. No, not people; I'm talking about a massive col- elephants. Our cover story by Deha and Mark Owens, about ony of wild the aftermath of many years of elephant poaching in Zambia's North West Indian Luangwa National Park ("Comeback Kids," page 22), tells of another flamingos striking likeness between our species and elephants, revealed only in (Phoeiiicoptems times of desperation. Elephants from ravaged famihes act just like kids

ruber ruber). The resident birds firom broken homes. Young males form gangs and raise heU. Adoles- about 50,000 of them—nest cent females get pregnant. The focus of social hfe shrinks from the around the salty flats of Lake extended family to the single mom and her only calf The lore of Rosa, a reservoir ringed by man- elephant society, vested in elders, dies with them. The good news is grove trees. Photographer Solvin that, thanks to the efforts of the authors and others, poaching has been

Zankl chose one of the man- all but ehminated in the park. The bad news is that the consequences groves as a "hide." To minimize of poaching Hve on. the disruption, he installed him- Graciela Flores has a different perspective on consequences; afiier years self and his camera at the end of of careful scientific work, she doesn't see many. Flores smdied heat- the breeding season, when only sensing in the blood-sucking "assassin bug" of Latin America, the insect ten pairs of nesting flamingos vector of Chagas' disease ("In the Heat of the Night," page 32). The

were still mouth-feeding their ultimate goal of her research was to control a protozoan infection that newborn chicks. afflicts soine 20 irdUion people in the region. But the substantial scien-

Parent flamingos usually have tific knowledge of the assassin bug's behavior rarely seems to translate

one ofispring each year, which into actions that could sharply reduce its impact. Money for fighting

they nurture jointly. Rather than Chagas' disease is tight: although it may count Charles Darwin among

regurgitating food for it, both its illustrious victims, the disease, Flores notes, has been mostly an afflic- mom and dad secrete a bright tion of the poor. Research remains the province of a few dedicated sci- red, nutritious liquid in their entists. The thatch-roofed houses where the insects thrive remain home crop called "flamingo milk." The to 120 iniUion people—all at risk of a malady that can kiU or debilitate, color of the milk—and the rose virtually without warning. Flores has now traded the lab bench for a hue of the adults' feathers career in science journalism (she is an editor-at-large for this magazine). comes from high levels of hydro- carbon pigments (alpha- and be- ta-carotenes) in their diet. Fly Edmond A. Mathez presents another kind of epilogue, in his story of larvae and other microgoodies geological discovery in a remote corner of Antarctica ("Cold Fire,"

are the birds' main fare, filtered page 26). Long before it was covered with ice, Antarctica was part of a out fi-om lake water through the supercontinent geologists call Gondwana. One hundred eighty million flamingo's pumplike beak. years ago, parts of what was to become the frozen continent were Unlike the baby pictured wracked with violent volcanism, the surface repeatedly covered with here—a two-day-old hatchling hot lava, the underlying rock layers repeatedly pried apart by intruding most of the chicks Zankl ob- magma. Fast-forward in time, and a series of uplifts and deep cuts by ser\'ed were born a month earlier. ancient rivers exposed the underground "plumbing" of the molten Zankl fondly recalls the day rock. Miraculously, some of that plumbing occurs in valleys so dry they

several thousand chicks waddled harbor bare rock for all to see. past his hide, creating an incredi- Mathez and his colleagues reached this obscure Antarctic landscape ble splashing sound. "One chick as travelers from an unimaginably distant time (our present), to try to could not keep up with the make sense of the aftermath. Mathez's story encompasses hundreds of group and decided to stay be- millions of years and a continent-size portion of the Earth's surface.

!imd, between my tripod and But it begins in camp, where he and his twenty-tour companions toast my feet." After two hours, the their collective good fortune with Scotch whiskey splashed over

straggler finally rejoined the rau- 18,000-year-old glacial ice. Who says natural science is dry? cous group. —Erin Espelie —Peter Brown

6 NATURAL HISTORY July/August 2005 You Have an Important Engagement with Honduras

The Honduras Institute of Tourism, through its innovative —SAVE strategy, seeks to engage Scientific, Academic, Volunteer and Educational travelers in conserving and enhancing the country's diverse natural and cultural attractions. Scientists and academics can orient their research toward conservation goals,

and help us build our knowledge base, the better to interpret our unique resources to our visitors. Active engagement of SAVE travelers with our communities will provide invaluable opportunities to develop our human resources.

Honduras has much to offer SAVE travelers. Our system of parks is extensive and diverse, including world-class coral reefs, old-growth mangrove wetlands, vast tropical rain forests and cloud forests. Nine

cultural groups speak nearly as many languages. Copan is the artistic capital of the Maya world, and an important collection of non-Maya sites awaits discovery. Friendly and gracious, the Honduran people are eager to share perspectives on the myriad ways we humans adapt and thrive in this diverse world.

If you are interested in this unique Honduran initiative, contact the Honduras SAVE Program: Honduras SAVE Program Honduras Institute of Tourism HONDURAS 011-504-222-2124 Scieiifijk -Academe Vohmieer hducalional Tourim E-mail: [email protected] Nature's laboratory, culture's library. www.FundacionSAVE.com www.LetsGoHonduras.com CONTRIBUTORS

Before embarking on a career as a freelance photographer, SOLVIN ZANKL ("The Natural Moment," page 4) studied marine biolo- mm Peter Brown Editor-m-Chief gy at the University of Kiel in Germany. His scientific interests Mary Beth Aberlin Steven R. Black are evident in his focus on photographic essays featuring wild- Exemlive Editor Art Director life behavior. Zankl's work has been widely pubUshed, both in Board of Editors books and in such nature magazines as GEO and BBC Wildlife. Espelie, T. Kelleher, Erin J. Mary Knight, More of his award-winning wildlife images can be seen at his Avis Lang, Vittorio Maestro Michel DeMatteis Associate Managing Web site (www.solvinzankl.com). Editor Thomas Rosinski Associate Art Director Hannah Black, Assistant Art Director A geologist and curator in the department of earth and planetary Graciela Flores Editor-at-Large Liz Donohue, Rebecca Kessler, Kazmira Pytlak Interns sciences at the American Museum of Natural History in New York City, EDMOND A. MATHEZ ("Cold Fire," page 26) studies Contributing Editors Robert Anderson, Charles Liu, Laurence A, Marschall, the geochemistry of the volatile elements. His research interests Richard Milner, Robert H. Mohlenbrock, Joe Rao, include the soUdification of large magma bodies, the origins of Stephan Reebs, Adam Summers, Neil deGrasse Tyson platinum deposits, the electrical properties of rocks, and the early Earth. He has done fieldwork in many parts of the world, from Charles E. Harris Publisher the platinum mines of South Africa to the ancient rock-strewn mountains of Edgar L. Harrison Advertising Director Gale Page Consumer Marketing Director Greenland. This past he joined a group of geologists January on an expedition Maria Volpe Promotion Director to the McMurdo Dry Valleys of Antarctica, to study the ancient basalt deposits Sonia W Paratore National Advertising Manager Donna M. Ponzoni Production Manager known as the Ferrar dolerites. His most recent article for Natural History, "A Michael Shectman FulfiUnient Manager Birthstone for Earth," on zircon crystals, was published in May 2004. Jennifer Evans Business Administrator For advertising information call 646-356-6508 GRACIELA FLORES ("In the Heat of the Night," page 32) earned her Ph.D. in Advertising Saks Representatives biology at the University of Buenos Aires in Argentina. There Neii> York—Metrocorp Marketing, 212-972-1 157, she the entomologist met Josue Nunez and was drawn by Nunez's Duke International Media, 212-986-6098 contagious enthusiasm to the laboratory of insect physiology, run Defro/f—Barron Media Sales, LLC. 313-268-3996 C/jiCfl^t)—Robert Purdy & Associates, 312-726-7800 by Nunez and Claudio Lazzari, to study the behavior of vinclm- West Coast—On Course Media Sales, 310-710-7414

cas, or "assassin bugs." Flores subsequently left research to pursue Toronto—^American Publishers Representatives Ltd., 416-363-1388 a career in science writing and editing. She has designed biology Atlanta and A/won'—Rickles and Co., 770-664-4567 J National Direct Response—Sm)th Media Group, 646-638-4985 MM/y'f^m courses for high school teachers and co-authored two college- level biology textbooks, and has also completed a degree in science and environ- Todd Happer Vice President, Science Education mental reporting at New York University. Flores is now an editor-at-large at Educational Advisory Board

Natural History magazine, and freelances for publications such as T7ie Scientist. Myles Gordon American Musesnn of Natural History David Chesebrough Buffalo Museum of Science Stephanie Ratcliffe Natural History' Museum of the Adiromiacks Browsing the cultural anthropological hterature on ethnogenesis, the process by Ronen Mir SciTech Hands On Museum which new ethnic groups form, CHRISTOPHER M. STOJANOWSKI ("Unhappy Carol Valenta St. Louis Science Center Trails," page 38) reahzed that his dissertation research in physi- p Natural History Mag.\zine, Inc. cal anthropology might oSer clues to the rise of the Seminole, Charles E. Harris President, Chief Executive Officer the Indian nation that figures so prominently in the history of Charles Lalanne Chief Financial Officer Florida. His work, based on human remains excavated from Judy Buller General Manager archaeological cemeteries in Florida and Georgia, documents Cecile Washington General Manager Charles Rodin Publishing Advisor genetic changes among Native American groups during the

centuries. is sixteenth and seventeenth Stojanowski an as- To contact us regarding your subscription, to order a ne\\' sistant professor of anthropology at the Center for Bioarchaeological Research subscription, or to change your address, please visit our Web site www.naturalhistorymag.com or uxite to us at at Arizona State University in Tempe. Natural History RO. Box 5000. Harlan lA 51593-0257.

PICTURE CREDITS Cover: ©Roy Toft/Natioml Geographic Image Collection; pp. 4-5 & 6: ©Solvin Zankl/Namiepl.com; p. 12(car- Natural Hislory (ISSN 0028-0712) is published monihly, except for combined issues in July/Auguit and December/Januarj'. by Natural Hislory Ma^zinc. toon): ©Bud Grace; p. 12(top): ©Lake County Museuni/CORBIS; p. 12(bottom): ©Frans Lanting/Minden Pictures; p. 13(top): ©Kaitn Inc., in afHliition with the American Museum of Natural Hiitory. Centra! Warkenbn. Boston Univenity; p. 13{left): ©Nic Miller/Organics [mage Library; p. 14{top): ©Voller Emst/eStock Photo; p. I4(left): ©The Park Wes[ at 79th Street. New York. NY 10024. E-nuil: nhnugl^J natural Artist; p. 16; ©NASA/JPL; p. 18; ©Babakin Space Center, The Planetary Society; p 22: Mardn Harvey/NHPA; p. 23: Map by Joe LeMon- hiitorymag.coni. Natural Historj' Magazine, Inc.. is solely t«poiisible for edito- nier; p. 24: ©The Audior; p. 26-27: ©Andris Apse; p. 28: Maps by GecgraphX; p. 29: ©Bruce Marsh; p. 30: Diagram by Ian Worpole. re- rial content and publishing practices. Subscriptions: $30.00 a year; for Canada worked a from diagram by Bruce Marsh; p. 31: ©The Author; pp. 32-33: Illustration by Advanced Illustration; p. 34(left &; right): and all other countries: S40.00 i war. Periodicals postage paid at New York. NY, ©WHO/TDR/Stanimei^; pp 35 & 36: ©lllustrarions by Advanced Illustration; pp 38 & 39: ©CORBIS; p 40: CThe Library of Congress. and at additional mailing oRices, Canada Publications Mail No. 40030827. Geography and Division; Cop>Tight C' 2(Hi5 by NatunI Historv- Magaane. Inc- All rights nrserv-ed. No Map pp. 41&43: Maps by Joe LeMonnier; p. 42: Illustration by Patricia J. ^X/yT^ne; p. 44: ©Bridgeman Art Library; part of this periodical may be ivproduced without written consent of .Vonifj/ p. 46(leit): ©Wendy Shatdl/Bob Rozinski; pp. 46-47{top): ©Glenn Randall; p. 47: Map by Joe LeMonnier; p 48: ©USDA Forest Service; p. Hislory. If you would tike to contact as regarding your subscription or to enter a 48(inset): ©Barbara Sti-nadova/Photo Researchers, Inc.; p. 50: ©Russ Heinl and W. W. Norton & Company, Inc.; p. 52; ©Cynthia Hart De- new subscription, please WTite to us at Natural History. P.O. Box 5000, Hatlan. signer/CORBIS; p. 55: ©The Artist; p. 64: ©Bridgeman Art Library. lA 51593-0257, Postma.Mcr: Send address changes to S'aumt Hisioi): P O, Box

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8 NATURAL HISTORY July/August 2005 SJ ATM nAI Subscribe now and HISTORV SAVE Vo'46%*

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Dinosaur Geography Thomas E. William- chain, but also ate juve- Well, dorft] j -ItieY .sure

son, I published I li ke nile tyrannosaurs. Mark A. Norell and Xu and looK me! J Xing's tyrannosaur history shows that both Ap- David R. Schwimmer ["The Varieties of Tyran- palachiosatmis and Columbus State University nosaurs," 5/05] was lucid Dryptosmmis were Columbus, Georgia and informative, but I more primitive than ?£r^j^-=:= would amend their as- their contemporaries Mark A. Norell and

sumption that all North in the North Ameri- Xu Xing reply: Our American tyrannosaurs are can West. Ironically, article was in press before of Asian ancestry. During Dryptosaurus, the most the paper by David R. the Late Cretaceous the primitive tyranno- Schwimmer and his vast Western Interior Sea- sauroid, only appears colleagues was published, way spHt North America in the fossil record so the interesting results into East and West. If the nearly as late as the they found were not in- eastern genera Appalachio- least primitive, Tyran- cluded. With the sample saurus and Dryptosaurus are nosaurus. Dryptosaurus may evident in Asia and the they used in their study, they derived from Asia, their an- have been a "living fossil" in western United States. But cannot empirically reject an

cestors must have crossed its own time. It might be in the lowlands of the Asian origin for tyranno- the continent before the usefril to look east, to Eu- southern U.S. the gigantic saurs. Furthermore, several

sea was present, at least 1 00 rope, for its nearest ancestry. crocodilian, Deinosuchus, primitive key Asian taxa, rmHion years ago. Messrs. Norell and Xu grew to more than thirty- such as Dilong, Alectrosaurus,

Although that is plausible, also maintain that tyran- three feet long and was and Alioramus, were not in- a recent cladistic analysis nosaurs "hved at the top of very abundant. The animal cluded in their analysis. We that Thomas D. Carr, the food chain." That is not only topped the food (Continued on page 54)

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iii:tu332lJ-SS four. But the geneticists found only States Leprosarium on Molofcai, Hawaii four: C,G,A; C,T,A; C,T,C; and T,T,C.

Mapping out where and in what proportion each combination occurs today, the investigators realized, could track the spread of the disease through time and space.

Previously it was thought that

leprosy originated in India (which still

has the most cases) and was introduced into Europe when the armies of Alexander the Great returned from their Indian campaign. But Monot, Honore, and their colleagues now say

East Africa or the Near East is probably the birthplace of the disease. From there, leprosy spread around the globe via human migration, trade, and colonialism.

M. leprae was likely brought to West Africa, for instance, by infected explorers or traders from North Africa or Europe, then followed the slave laborators analyzed the otherwise ex- trade to the Americas. And emigration

Chain Letters tremely stable genome of Mycobacterium from Europe in the eighteenth and nine-

There's a game known as "word chains" in leprae, the microorganism responsible for teenth centuries may have brought

which you go from one word to another by leprosy, and discovered variations in the M. /eprae to northern North America:

changing one letter at a time (fiat, hot, dot, DNA sequence at three widely separated while a leprosy epidemic was taking place

doe). Geneticists sometimes see the same places in the genome. The DNA "alpha- in Norway, Scandinavian immigrants were thing happening with DNA. bet" has just four "letters"—A, C, G, and settling the Midwest and manifesting the Marc Monot and Nadine Honore of the T—and so the total number of possible disease. {Science 308:1 040-42, 2005)

Pasteur Institute in Paris and a host of col- combinations at those three places is sixty- —Stephan Reebs

Keeping an Eye Out

Like most animals, adult giraffes are a watchful crew. But even when they're alone, even when hungry lions and opportunistic hyenas may lurk nearby, and even when their own youngsters

could be in danger, giraffes seem more concerned about watching one another than watching out for predators.

A recent field study in South Africa's Kruger National Park by two biologists, Elissa Z. Cameron of the University of

Nevada-Reno and Johan T. du Toit of the University of Pretoria in South Africa, suggests that when giraffes periodically interrupt their lunch to scan their surroundings, they're mostly monitoring

the whereabouts of the local male giraffes. Small bulls and females are both more vigilant when large bulls are nearby. Animals generally face a trade-off between checking for possible predators and spending their time eating. Giraffes face an out for superior competitors: giraffe fights can be brutal indeed.

additional problem. Individual females are sexually receptive at vary- It also turns out that the giraffe's long neck can be more hindrance

ing times of year, and so lusty males are continually on the lookout than help. A giraffe holding its neck vertically to reach the uppermost

for a willing partner. But the males' attentions can interrupt the all- branches of a tree ends up looking at the sky, and can't see what its

important business of eating enough greenery to get through the neighbors are up to. So it, too, frequently interrupts its feeding and

day. Receptive females, say the biologists, are probably on the spends more time scanning its surroundings than do neighboring lookout for approaching males so that they can move away before giraffes that are feeding on the middle branches. [Animal Behaviour being pestered. And the younger, smaller males need to watch doi:10.1016/j.anbehav.2004.08.015, 2005) —Nick W. Atkinson

12 NATURAL HISTORY July/August 2005 Growing Strains Shakers and One must suffer to become beautiful, say Movers the French. So it is with the rose. IVIaking

all those gorgeous colors and alluring Eggs, whether from amphibians, birds, in-

scents does take its toll. According to sects, or reptiles, cannot move on their own, Alexander Vainstein and Mery Dafny- and few carry noxious chemicals. So when a

Yellin, molecular biologists at the Hebrew predator chances on a clutch of eggs with

University of Jerusalem, and their collab- no parent in sight, it's breakfast time! Case

orators, each rose petal produces almost in point: a mass of red-eyed treefrog eggs

a thousand different proteins, a fair share , glued to a leaf above a tropical pond. But as of which are devoted to fighting stress. soon as a snake chomps down on that

As the petals emerge from their pro- clutch, breakfast is likely to change from lav-

tective covering, the sepals, and turn into ish Sunday brunch to basic continental.

a full-fledged but still-closed flower, they Karen M. Warkentin, a biologist at Boston

University, has discovered that if the frog

embryos are in the final third of their development, a predator attack on their egg clutch leads to quick group action. The em-

bryos wriggle frantically, break out of the

capsule that detains them, and drop into the As a snake shakes a mass of frog eggs, an water below. Because the escapees are not embryo escapes and hatches (center right).

yet fully developed, they may soon fall prey to other predators—but any chance of sur- then mimicking the shaking of an egg clutch

i viva! is better than certain demise in the gut under attack by a snake, Warkentin has of the snake. shown how well the embryos can distinguish

What triggers the embryos' response? the telltale signs of an important predator

It's the precise pattern of vibrations caused from the tremors caused by innocuous dis- by the snake's first few bites. The soon-to- turbances such as rain—and how well-devel- be frogs react by hatching a day or even oped an embryo's decision making can be.

acquire their familiar color, and treble or two days earlier than their usual six- to {Animal Behaviour doi:1 0.1 01 6/j.anbehav.

quadruple their weight. Subsequent seven-day stint on the leaf. By recording and 2004.09.019,2005) —S.R. growth, and the opening of the flower, comes from the very rapid expansion of sulfur isotopes in vermillion already existing cells in the petals, rather the from Red Power twelve ancient than from the addition of new cells. To mounds, because the ratios millennia, indelible study the process in detail, the investiga- For the vivid orange-red serve as "birthmarks." Then they tors divided flower development into pigment called Vermillion has decorated compared those isotope ratios with the ra- pottery and preserved royal bones. tios in vermillion from three central Japan- three stages—tightly closed bud, fully colored but loosely closed flower, fully Recently a team of geologists and archaeol- ese mines, as well as from an important an- open flower—and analyzed how much of ogists, led by Takeshi IVIinami, an environ- cient mine in Guizhou province, China. each kind of protein was present at each mental chemist at Kinki University in Osaka, Vermillion from the Chinese mine, they stage. They expected essentially the Japan, traced large quantities of the prized found, is high in sulfur-34; vermillion from same proteins to persist throughout the pigment found in some central Japanese the central Japanese mines, in and around

burial their local in the kingdom, is far richer in sulfur- flowering process, though perhaps in mounds to source: mines Yamato varying quantities. the ancient Yamato kingdom, which flour- 32. Correlating the ratios showed that the Instead, they found that only about 40 ished early in the first millennium a.d. in vermillion in the western Japanese burial percent of the proteins were present at central Japan. Controlling access to those mounds originated in China, whereas the every stage. Almost 30 percent made just mines may have been an important element vermillion in the central Japanese a single-stage appearance, and then were of Yamato realpolitik. mounds—datable to the time of the Yama-

gone. What a lot of change for a romantic Funerary uses of Vermillion, a form of to kingdom—was local. emblem to endure! No wonder nearly 20 mercuric sulfide, were common in China One way the Yamato clan built alliances before they spread to Japan. with neighbors to distribute their stash percent of the rose's proteins were in- western To was Chinese bronze mirrors. Handing out lo- volved in fighting stress, and that most of find the source of the central Japanese Ver- of cally vermillion, the investigators, them were not only present at every million, and thus help trace the region's po- mined say litical history, investigators have been another. {Ceoarchaeology stage but also increased in quantity as the measured may the flower matured. (P/anta doi:10.1007/ the relative abundances, or ratios, of two 20:79-84, 2005) —Caitlin E. Cox S00425-005-1512-X, 2005) —S.R.

July/August 2005 NATURAL HISTORY 13 SAMPLINGS

Play Ball! not see a difference until the sec-

All summer long, kids will be wait- ond grid moved more than twice ing eagerly to catch balls tossed that fast; the adults required a by Dad or Grandma. And more speed-up of only one-third.

than likely, they're going to wait But when the first grid sped too long: the grown-up, intending along at six degrees a second

an easy catch, will make a slow (equivalent to a ball approaching toss that turns out to be just the at twenty-four feet a second), reverse of easy. A group of Cana- both groups saw the difference dian investigators has now shown that kindergarteners—and their much more readily. The kids became accurate when the second grid parents—can much more readily assess the speed of faster-moving moved just 44 percent faster than the first grid; the adults were accu- objects than that of slower ones. rate with a speed-up of just 13 percent. in Terri L. Lewis, a neuroscientist at McMaster University in Hamilton, According to the investigators, it's all about the neurons the in re- Ontario; Iram J. Ahmed, now a medical student at Queen's University middle temporal area of the brain. Few of them specialize

in Kingston, Ontario; and their colleagues tested five-year-olds and sponding to dawdlers, and those few take many years to mature. adults (average age twenty) on speed assessment. Each subject was In any event, being better at noticing speed than noticing slow- asked to watch two grids of identical stripes, both shown moving ness was a useful bit of evolution for the human race, making it across a computer monitor, and to say which was moving faster. easier for our ancestors to close in on a four-legged dinner sprint-

When the "reference grid" moved slowly, at 1 .5 degrees a second ing across the savannah. So go ahead, put some heat on that bail! (equivalent to a ball approaching at six feet a second), the kids could (Vis/on Research 45:2129-35, 20 —Elizabeth M. Donohue By Any Means Available

Sex in the microbial realm is, as you might expect, not quite the same thing as what

people like to do in their spare time. But it does take place. The fungus Cryptococcus neoformans, for instance, has two "sexes" (more techni-

cally, mating types): alpha and a. According to new research by Xiaorong Lin, a microbi-

ologist at Duke University in Durham, and her colleagues, the alpha type swings both

ways: it can exchange genetic material not only with a individuals but also with other al-

Yoju, Heart Mountain. 1997 phas. The two processes are different—^the Air Hockey for Giants same-sex one requires the formation of a

The Heart Mountain rockslide in northwest- glass. The grains, the investigators point out, fruiting body, which is inefficient—but both fusion of haploid ern Wyoming is the world's largest rockslide are much like the ones that often form in gas require pheromones, the and one of geology's biggest puzzles. What clouds released by volcanic eruptions. Beut- cells (cells with just one copy of each chro- could cause a mass of rock nearly 450 square ner and Gerbi say the microbreccia layer is mosome), and meiosis, all of which are hall- Furthermore, miles in area, and weighing trillions of tons, made of fragments carried in a gaseous marks of sexual reproduction.

to slide along a stretch of nearly flat ground cushion that "greased" the surface along both produce spores. newly and end up, in a matter of minutes, as a which the rocks slid 48 million years ago. When you add C. neoformans's flexibility to its known ca- sheet of rubble covering about 1 ,300 square The slide was probably triggered by a examined sexual miles? Two geologists, Edward C. Beutner of nearby volcanic eruption. Then the heat and pacity for cloning itself (asexual reproduc- or- Franklin and Marshall College in Lancaster, pressure generated by the friction of the tion), you're looking at populations of lot potential to adapt to Pennsylvania, and Gregory P. Gerbi of the moving mass caused the limestone below it ganisms with a of Massachusetts Institute of Technology, have to break down, releasing a cloud of carbon new conditions as well as to multiply rapid- fun- a theory: the slide was a gas. dioxide gas that floated the rubble. Re- ly. And that's bad news, because this Beutner and Gerbi examined an unusual lieved of the ordinary friction of rock on gus (most likely, its spores) causes menin- layer of rock known as a microbreccia, lying rock, the slide could have traveled extraor- goencephalitis in people whose immune along the fault on which the Heart Mountain dinary distances at a hundred miles an hour. systems can't put up a fight. {Nature

rocks broke free and slid. That layer holds {GSA Bulletin 117:724-35, 2005) 434:1017-21,2005) minute grains of carbonate rock and volcanic —Dave Forest —S.R.

14 NATURAL HISTORY July/August 2005 CAMBRIDGE

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To explore deep space—and make stops along the way—spacecraft will need newforms ofpropulsion.

By Neil deGrasse Tyson

down, it can't deprived craft. In the case of the Mars Launching a spacecraft is now a Ifa spacecraft can't slow routine feat of engineering. At- land anywhere without crashing, which Rovers, their breakneck speed toward aero- tach the fuel tanks and rocket is not a common objective of aerospace the Red Planet was slowed by boosters, ignite the chemical fuels, and engineers. Lately, however, engineers braking through the Martian atmosphere. That meant they could land with away it goes. have been getting clever about fuel- But today's spacecraft quick- the help of nothing more than parachutes airbags. ly run out of fiiel. In fact, by and biggest challenge the time a craft exits Earth or- Today, the aeronautics is to find a Hght- bit, there's no fuel left in its in efficient means of main tanks—which, no longer weight and needed, have dropped back to propulsion, whose punch per of Earth. Only tiny tanks remain, pound greatly exceeds that permitting only mild mid- conventional chemical fuels. course corrections. All the With that challenge met, a spacecraft could leave the spacecraft can do is coast to its reserves destination. launchpad with fuel and use them much And what happens when it onboard, arrives? later. Scientists could think celestial objects as Without the benefit of fill- more about planetary ing stations or sizable tanks of places to visit than as spare fuel, the craft cannot be peep shows. made to slow down, stop, Formnately, human ingenu- speed up, or make serious ity doesn't often take no for an Legions of engineers changes in direction. With its answer. our trajectory choreographed en- are ready to propel us and surrogates into deep tirely by the gravity fields of robotic the Sun, the planets, and their space with ion thrusters, solar nuclear reactors. The moons, the craft can only fly saUs, and most efficient engines would by its destination, hke a fast- moving tour bus with no tap energy from a nuclear reactor by bringing matter and stops on its itinerary—and the contact with riders can only glance at the antimatter into passing scenery. That's what each other, thereby converting happened with the Pioneer all their mass into propulsion anti- and Voyager spacecraft in the energy, just as Star Trek's 1970s and 1980s: they simply matter engines did. Some careened from one planet to physicists even dream of travel- ing faster than the speed of the next on their way out of Poster for Deep Space 1 , a NASA spacecraft tunneling the solar system. launched in 1998 light, by somehow

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- The Boston Globe Rosetta^one Language Learning ^^Hik Success through warps in the fabric of space ergy that accelerates it. Deep Space 1 first ionize the xenon atoms and then and time. Star Trek didn't niiss that one used electrically charged (ionized) accelerate them. That energy came either: the warp drives on the starship xenon gas as its propellant, rather than from electricity, courtesy of the Sun. USS Enterprise were what enabled Cap- the liquid hydrogen-oxygen combo For touring the inner solar system, tain Kirk and his crew to cross the galaxy burned in the space shuttle's main where Ught from the Sun is strong, the during the TV commercials. engines. Ionized gas is easier to man- spacecraft of tomorrow can use solar age than explosively flammable chem- arrays—not for propulsion itself, but for In October 1998, an eight-foot-tall, icals. Plus, xenon happens to be a no- the electric power needed to drive the half-ton spacecraft called Deep Space ble gas, which means it won't corrode equipment that manages the propul-

1 launched from Cape Canaveral, or otherwise interact chemically with sion. Deep Space 1 has folding solar

Florida. During its three-year mission, anything. For 16,000 hours, using less "wings." Fully extended, they span al- Deep Space 1 tested a dozen innovative than four ounces of propellant a day. most forty feet—about five times the technologies, including a propulsion Deep Space Vs foot-wide, drum-shaped height of the spacecraft itself The arrays system equipped with ion thrusters. engine accelerated xenon ions across on them are a combination of 3,600 so- Acceleration can be gradual and an electric field to speeds of twenty- lar cells and more than 700 cylindrical prolonged, or it can come from a brief, five miles per second and spewed them lenses that focus sunlight on the cells. spectacular blast. Only a At peak power, their col- major blast can propel a lective output was more spacecraft off the ground. than 2,000 watts, enough to You've got to have at least operate only a hair dryer or as many pounds ofthrust as two on Earth but plenty for the weight of the craft it- powering the spacecraft's self. Otherwise, the thing ion thrusters. And last I willjust sit there on the pad. heard, the radio was still on. After that, ifyou're not in a Other, more familiar big rush—and if you're spacecraft—such as the sending cargo rather than now-disintegrated Soviet crew to the distant reaches space station Mir and the of the solar system—there's nearly seven-year-old In- no need for spectacular ac- ternational Space Station celeration. And that's when (ISS) —have also depended ion thrusters work best. on the Sun for the power lon-thruster engines do to operate their electron- what conventional space- ics. A work-in-progress craft engines do: they accel- orbiting about 250 miles erate propeUant (in this case, above Earth, the ISS wiU a gas) to very high speeds eventually carry more than and channel it out a nozzle. an acre's worth of solar In response, the engine, and panels. For about a third of thus the rest of the space- every ninety-minute orbit,

Cosmos 1 , shown here in an artist's conception, is craft, recoils in the opposite as Earth eclipses the Sun, intended to be the first solar sail placed in orbit around direction. You can do this the station orbits in dark- Earth. Its launch is scheduled for this summer. When all its day, the science experiment your- sails are fully unfurled, the craft will be propelled solely by ness. So by some of self While you're standing the pressure of the Sun's rays. collected solar energy gets on a skateboard, let loose a channeled into storage bat-

CO2 fire extinguisher (purchased, of from its nozzle. As anticipated, the re- teries for later use during dark hours. course, for this purpose). The gas will coil per pound of fuel was ten times Although neither Deep Space 1 nor go one way; you and the skateboard will greater than that of conventional the ISS uses the Sun's rays to propel it- go the other way. This equivalence of rocket engines. self, direct solar propulsion is far from

action and reaction is a law of the uni- impossible. Consider Cosmos 1, an en- verse, first described by Isaac Newton in In space, as on Earth, there is no such gineless, 220-pound spacecraft that the late seventeenth century. thing as a free lunch—not to men- will be propelled (once it achieves But ion thrusters and ordinary rock- tion a free launch. Something had to Earth orbit) solely by the pressure of et engines part ways in their choice of power those ion thrusters on Deep Space sunlight. In fact. Cosmos ? is a solar sail.

it propellant and their source of the en- 1 . Some investment of energy had to By the time you read these words,

NATURAL HISTORY July/August 2005 may have entered its initial intended other edible items of extremely high orbit, 500 miles above Earth. The pro- shelfhfe. And as the craft sailed into sec- ^^GofTTiplete ject is a privately funded collaboration tors where the Sun's hght is feeble, you Woj^ldof: between U.S. and Russian space sci- could help it along with a laser, beamed

entists, led by The Planetary Society. from Earth, or with a network of lasers ^ .Human This summer's launch will culminate stationed across the solar system. ^Evolution nearly five years ofwork by rocket sci- Speaking of regions where the Sun

entists who would rather collaborate IS dim, suppose you wanted to park a than contribute to mutual assured space station in the outer solar sys- destruction (aptly known as MAD). tem—at Jupiter, for instance, where Shaped like a supersize daisy, this sunlight is only 1/27 as intense as it

celestial sailboat folds inside an un- IS here on Earth. If your Jovian space armed intercontinental ballistic missile station required the same amount of left over from the Soviet Union's cold solar power as the completed Interna- war arsenal, and then launches from a tional Space Station will, your panels

Russian submarine. Cosmos 1 has a would have to cover twenty-seven '4'\ computer at its center and eight reflec- acres. So you would now be laying tive, triangular sail blades made of solar arrays over an area bigger than Mylar reinforced with aluminum. twenty football fields. Fuggedaboutit. When unfurled in space, each blade ex- To do complex science in deep

tends fifty feet yet is only 0.0002 inch space, to enable explorers (or settlers) thick—much thinner than a cheap to spend time there, to operate equip- trash bag—and can be individually an- ment on the surfaces of distant planets, gled to steer and sail the craft. you must draw energy from sources other than the Sun.

nee aloft, the solar sail will accel- o erate because of the continual, Since the early 1960s, space vehicles collective thrust of the Sun's gaziUion have commonly relied on the heat

photons, or particles of Ught, hitting its from radioactive plutonium as a pow- blades and bouncing off the reflective er supply. Several of the Apollo mis- surfaces. As they bounce, the photons sions to the Moon, Pioneer 10 and 11

will give rise to a gazilHon little recoils (now more than 8 biUion miles from in the opposite direction. No fuel. No Earth, and headed for interstellar

fuel tanks. No exhaust. No mess. You space). Viking 1 and 2 (to Mars), Voy-

can't get greener than that. ager 1 and 2 (also destined for inter- Having entered space, a lightweight stellar space and, in the case of Voyager

solar sail could, after a couple of years, 1, farther along than the Pioneers), and accelerate to 100,000 miles an hour. Cassini (now orbiting Saturn), among

Such a craft escapes from Earth orbit others, have all used plutonium for

(where it was deposited by conven- their radioisotope thermoelectric

tional rockets) not by aiming for a generators, or RTGs. An RTG is an

destination but by cleverly angling its inefficient but long-lasting source of blades, as does a sailor on a ship, so that nuclear power. Much more efficient,

it ascends to ever-larger orbits around and much more energetic, would be a

Earth. Eventually its orbit could be- nuclear reactor that could supply both

come the same as that of the Moon, or power and propulsion. Mars, or something beyond. Nuclear power in any form, of

Obviously a solar sail would not be course, is anathema to some people. the transportation of choice if you're Good reasons for this view are not hard

in a hurry to receive supplies, but it to find. Inadequately shielded pluto- would certainly be fuel efficient. Ifyou nium and other radioactive elements

wanted to use it as, say, a low-cost food- pose great danger; uncontrolled nu-

dehvery van, you could load it up with clear chain reactions pose an even

freeze-dried veggies, ready-to-eat greater danger. And it's easy to draw

breakfast cereals. Cool Whip, and up a list of proven and potential disas- "^J^ Thames & Hudson Available wherever books are sold thamesandhudsonusa.com —

ters: the radioactive debris spread needs of a small school—or a single luminal quantum phenomena. Their across northern Canada in 1978 by SUV. To exploit the Promethean ad- inspiration came from such tales as

the crash of the nuclear-powered So- vance, an ambitious scientific mission From the Earth to the Moon, by Jules viet sateUite Cosmos 954; the partial has been proposed: the Jupiter Icy Verne, and the adventures of Buck meltdown in 1979 at the Three Mile Moons Orbiter, or JIMO. Its destina- Rogers, Flash Gordon, and Star Trek.

Island nuclear power plant on the Sus- tions would be Callisto, Ganymede, It's okay to think about this sort of quehanna River near Harrisburg, and Europa—three of the four moons thing from time to time. But, in my Pennsylvania; the explosion at the of Jupiter discovered by Galileo m opinion, though it's possible not to Chernobyl nuclear power plant in 1610. (The fourth, lo, is studded with have read enough science fiction in

1986 in what is now Ukraine; the plu- volcanoes and is flaming hot.) The lure one's hfetime, it's also possible to have

tonium in old RTGs currently lying in of the three frigid Galilean moons is read too much of it. (and occasionally stolen from) remote, that beneath their thick crust ofice may My favorite science-fiction engine

decrepit Hghthouses in northwestern he vast reservoirs of hquid water that is the antimatter drive. It's 100 percent

Russia. The list is long. Citizens' or- harbor, or once harbored, hfe. efficient: put a pound of antimatter ganizations such as the Global Net- Endow^ed with ample onboard together with a pound of matter, and work Against Weapons and Nuclear propulsion, JIMO would do a "flyto," they turn into a puff" of pure energy,

Power in Space remember these and rather than a flyby, ofJupiter. It would with no by-products. Antimatter is other similar events. puU into orbit and systematically visit real. Credit the twentieth-century one moon at a time, perhaps even de- British physicist Paul A.M. Dirac for But so do the scientists and engi- ploying landers. Powered by ample conceiving of it m 1928, and the neers who work on NASA's Pro- onboard electricity, suites of scientific American physicist Carl D. Anderson

ject Prometheus. instruments would study the moons for discovering it five years later.

The science part ofantimatter is fine.

It's the science-fiction part that presents science-jiction engine is dy favorite a small problem. How do you store the he antimatter drive. Put antimatter stuff? Behind whose spaceship cabin or under whose bunk bed would the can- nd matter together, and they turn into ister of antimatter be kept? And what puff ofpure energy. substance would the canister be made of? Antimatter and matter annihilate each other on contact, so keeping anti- Rather than deny the risks ot nuclear and send data back to Earth via high- matter around requires portable mat-

devices, NASA has turned its attention speed, broadband channels. Besides terless containers, such as magnetic to maximizing safeguards. In 2003 the efficiency, a big attraction would be fields shaped into magnetic botdes. Un- agency charged Project Prometheus safety, both structural and operational. Uke the fringe propulsion ideas, where with developing a small nuclear reac- The spacecraft would be launched engineering chases the bleeding edge ot

tor that could be safely launched and with ordinary rockets, and its nuclear physics, the antimatter problem is ordi- could power long and ambitious mis- reactor would be launched "cold" nary physics chasing the bleeding edge sions to the outer solar system. Such a not until JIMO had reached escape ve- of engineering. reactor would provide onboard power locity and was well out of Earth orbit So the quest continues. Meanwhile, and could drive an electric engine with would the reactor be turned on. As of next time you're watching a movie in ion thrusters—the same kind of this writing, however, plans for JIMO which a captured spy is being ques- propulsion tested in Deep Space 1. are on hold: a series ofsimpler missions tioned, think about this: The ques- To appreciate the advance of tech- wiU more expeditiously test the new tioners hardly ever ask about agricul- nology, consider the power output of Promethean propulsion systems. tural secrets or troop movements. With the RTGs that drove the experiments an eye to the future, the)- ask about the on the Vikings and Voyagers. They sup- Someday there might be wackier secret rocket formula, the transporta- plied no more than a hundred watts, ways to explore within and be- tion ticket to the final frontier.

about what your desk lamp uses. The yond our solar system. The folks at [This is part two of a two-part article.] RTGs on Cassini do a bit better: they NASA's now-defunct Breakthrough Astrophysicist Neil deGnissc Tyson is the di- could power your thousand-watt Propulsion Physics Project, for in- rector of the Haydcii Plauetiniiim at the Amer- microwave oven. nuclear reactor stance, were dreaming of how to cou- The ican Museum of Natural History. His latest

that will emerge from Prometheus ple gravity and electromagnetism, or book, co-aiithored with Donald Goldsmith, is should yield as much as 200,000 watts tap the zero-point energy states of the Origins: Fourteen Billion Years of Cosmic of power, equivalent to the energy quantum vacuum, or harness super- Evolution (U:u: Norton, 2004).

20 NATURAL HISTORY July/August 2005 OTi

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the inid-l 990s. When we arrived in the park, in the middle of this devastating Comeback Kids period, the Zambian government simply did not have the resources to stem the onslaught. problem was the park's re- Elephant "single moms" are struggling to recreate Part of the mote wilderness. It is nesded under the family life after the traumatic years ofpoaching. shoulder of the Muchinga Escarpment, where waterfalls tumble a thousand feet

over forested mountains [see map on op- Delia By and Mark Owens posite page]. To the east ofthe mountains,

the wide Luangwa River snakes its way There—a baby! She is coming As we watched her, Patrick whis- through a valley, creating enormous to us by the river," Patrick pered what each of us was thinking: floodplains and habitat for Cape buffa-

Mwamba, a Bemba tribes- "She is very much alone in this place." lo, Cookson's wildebeest, puku ante- man, whispered. Across the river from Another orphan. They had become lope, and zebras. In 1986, gliding over our camp a small female elephant trot- commonplace here, in North Luang- the plains for the first rime and peering ted along the shore, her trunk flopping wa National Park (NLNP), Zambia. down from our small airplane, we saw a loosely like a garden hose. Abruptly, From the late 1970s through the 1980s, landscape that looked wild and free. In

she stopped and looked into the tall commercial poachers had shot 93 per- fact, though, poachers had taken it over. grass, then turned and walked slowly cent of the elephants in the population Bands of as many as a hundred men had south. Holding her httle trunk in the for their ivory, skin, or meat. The pop- set up makeshift encampments, from

air like a periscope, she twisted the end ulation had declined from 1 7,000 in the which they would sally forth to shoot

around in all directions. mid-1970s to approximately 1,500 by elephants and lions. Then, like scurry-

22 NATURAL HISTORY July/August 2005 —, .

ing ants, they would carry the illegal large sums ofmoney from ivory, so they throughout their lives, and each family ivory and meat over the escarpment, could no longer afford to hire villagers unit is led by a matriarch that, in the where it was sold to smugglers. to be shooters or porters. days before widespread poaching, could For more than 200 years, the high Finally the poaching declined to live to be sixty years old. Grandmoth- value ofivory and other elephant prod- fewer than ten elephants killed in 1 99 1 ers, mothers, aunts, sisters, and female ucts have made hunting and poaching and even fewer per year in the next cousins feed together, romp in the ongoing facts ofHfe for elephants, both decade. Still, a few elephants were be- rivers, and play on the plains. There is a in Africa and in Asia. The easiest way ing shot. The entire family of the or- lot of touching and bumping of body to get the ivory has always been to kill phan that Patrick spotted had been parts, and the animals, like afiectionate the giant creatures, and as firearms have mowed down with machine guns, be- tanks, show very little aggression to- become more common, more accu- fore she made her way to our camp. ward each other. rate, and more deadly in the past two Young males stay in the group into centuries, more elephants have been Patrick and the two of us watched which they were born until they reach killed. The elephants ot Luangwa were, as she slowly dropped her trunk. puberty (nine to fourteen years ot age) to some extent, protected by their re- Since they are related to every female mote location and by the ruggedness of in their natal family unit, when testos- the terrain. In the early years of the terone kicks in, they leave the security ivory trade they had fewer losses than of the unit in search of a suitable mate. did elephants in other, more densely Adult males spend much of their time human-inhabited areas, such as South alone, or with several other males that Africa. But by the late 1970s, intense stay together while feeding. When a re- poaching finally reached NLNP. There ceptive female comes along, however, were stiU 5,000 elephants in the park It's every bull for himself when we arrived in 1986, but the Young females learn a great deal poachers were .shooting about a thou- about maternal behavior from their el- sand every year. ders. Long before they are old enough to reproduce or lactate, female adoles- Working with the Zambian Na- cents "practice" the art of nursing in- tional Parks and WildUfe Ser- fants by putting one forefoot forward; vices and the Anticorruption Com- for a mother and her calf that move- mission, we assisted government game ment gives the calf easier access to its scouts by providing housing, trucks, North Luangwa National Park, where the mother's teats. If any infant in the fam- uniforms, and food for their patrols. authors have studied the effects of poaching ily squeals, all the females run to its on elephant populations, lies in northeastern With new training and incentives, the aid—pulling it out of the mud, push- Zambia. The park is approximately the size of scouts began capturing poachers. ing it up an embankment. the state of Delaware. But even more important, in four- The old matriarchs are the group's teen outlying villages we set up the walked into the tall grass, and disap- storehouses of knowledge. They know North Luangwa Conservation Project peared. We crossed the shallow river, the water sources in times of drought, (NLCP), which offered alternative keeping an eye out for Ripples, a croc- the ancient routes across the mountains jobs, rural health care, and conserva- odile that frequented the pools and ed- for the best dry-season forage. They tion education. Poaching is not only il- dies near camp. We studied the foot- lead the other elephants across the Lu- legal, it is dangerous and not very prof- prints the Httle elephant had left in the angwa River in darkness to avoid the itable for the vUlagers. Ivory smugglers white-hot sand. African elephants grow poachers. The matriarch's guidance is paid vUlagers only ten dollars for shoot- throughout their lives, so one can esti- the glue that holds the elephant fami- ing an elephant. With the village jobs mate their ages by measuring the length ly together, making it among the most program in place, many of the former of their hind footprints. The method is social and cooperative groups of ani- poachers and other villagers became particularly accurate up to fifteen years mals on Earth. beekeepers, fish farmers, millers, or ofage, and so we were fairly certain from But Uttle Gift was alone. She was ob- sunflower-press operators. Men and our measurements that the orphan was viously weaned or she would not have women had safe, profitable jobs that fed about five years old. We named her Gift; survived, but she had no family mem- and supported their families. we didn't expect to see her again. bers to touch her, to lead her, or teach Another tool that proved essential in African elephants usually live in tight her the ways of the elephant world. the struggle against poaching was the social groups—in fact, family units The next day Camp Group—a loose international ivory ban, adopted in whose gene Unes persist for genera- alliance of males that often visited our 1989. Smugglers could no longer make tions. Females remain within the group camp to eat the crab-apple-Uke maru-

July/August 2005 NATURAL HISTORY 23 la fruit—wandered across the river and dividuals to only five. The age structure Almost three years after we first saw fed on the tall grass by our cottage. had also been heavily skewed: only 6 Gift, Patrick Mwamba walked Forty yards behind them was the percent ofthe population was older than softly to our cottage and knocked on

diminutive Gift. Abandoning all nor- twenty. Before the most recent fifteen- the door. "Come see," he said. "The mal elephant behavior in the absence year stretch of severe poaching, more baby elephant, the one you call 'Gif- of a female family, Gift had taken up than half the elephants in a neighboring tee,' has got a baby." residency with the Camp Group males. population had been older than twenty. "What! That's impossible." Gift Almost every day we could see her In fact, females between twenty and could not be more than eight and a half feeding near them. forty-five years old had been the most years old. She was only half the age at Now and then Gift would walk up reproducrively active members of pop- which females usually gave birth. to Survivor, the first male to accept our ulations in which poaching was not se- But sure enough, we found Gift with presence after poaching was reduced, vere. Now very few females in that age a small, dark-gray infant at her side. At or to Long Tail, another male in Camp group in the NLNP remained aHve. first we thought it might be another

Group, whose tail was so long it almost No longer were massive and wise old orphan, clearly too small to survive on touched the ground. She would hold matriarchs leading the family units. A its own, but looking to Gift for securi- up her toy-size trunk to theirs in ty. But we soon saw the Httle fe- greeting. But the males ignored male nursing and knew for sure

her; after all, she was much too that it was Gift's daughter. We young for breeding. In our expe- named her Georgia. rience, females did not ovulate be- At eight and a half, Gift had before the age of eleven, and usual- come a single mom. Single moms ly not until age fourteen. They are almost unheard of in normal never gave birth before age six- elephant populations. Before the teen. Gift was only five. So instead severe poaching in Luangwa, fam- of reaching out a trunk or bump- ily units of two elephants made up ing foreheads, as her mother or only 3 percent ofthe total. But our aunts would have done to Gift, the data told us that now one-quarter males turned their backs to her. of the elephant families in North Gift's first calf Georgia, shares a cfrinfc at a river with Luangwa were made up of just a her mother, in North Luangwa National Park. Gift, an ten years we studied the ef- single mother and her first calf. For orphan elephant, became a "single mom" at the age of fects ofthe severe poaching on Of course, the infants born to eight. Because of poaching, a quarter of the family

the NLNP elephant population. units in the park include just a mother and a single calf. single moms were not surround- We fitted radio collars on one fe- Before poaching became common, Gift and Georgia ed by grandmothers, aunts, female male in each of sixteen family would have had calf-rearing help from a group of cousins, and sisters. Investigators female relatives; now, they are on their own. units, and measured the footprints in East Africa have determined ofmost ofthe remaining elephants, that in normal unstressed, un- thereby determining the ages of the third of the units included no adult poached populations of elephants, aUo- population. female older than fifteen years. Eight mothering—care given by female rela- One of the most striking effects of percent of the groups were made up tives other than the mother—greatly poaching we documented was that by entirely of orphans. Young males, enhances the survival of a call. Other the 1990s, 38 percent ofthe NLNP ele- which, in an undisturbed elephant females of the family group even help

phants were tuskless. In elephant pop- society, would still be living in their remove the birth sac from newborns. ulations where poaching had not been mothers' groups, formed groups oftheir But Georgia had no one but Gift. a problem, approximately 2 percent of own. They reminded us of inner-city What was most amazing to us, how- elephants had no tusks. Because poach- gangs, chasing nonreceptive females and ever, was that Gift had given birth at ers had obviously selected individuals fighting among themselves. The NLNP such a young age. We thought that per- for their tusks, the percentage ofthe ele- elephant population had essentially haps she was a fluke. Because she was phants remaining without tusks had been reduced to groups of teenagers. an orphan, and because she hung out greatly increased. But the makeup of the groups also with males all the time, never with

But it was not just the number of ele- posed a mystery. Many of the family adult females, she had become preg- phants or the presence of tusks that had units had more infants than adult fe- nant against all odds. But at least it gave changed with poaching. Their very so- males. Elephants do not normally adopt us a good opportunity to observe the cial structure was being transformed. orphans, so how was such a shift pos- maternal behavior of an orphan.

The average size of the family unit had sible? It would take us years to unravel By that time. Gift had accepted us been cut almost in half; from eight in- that question. completely, and so Georgia did, too.

24 NATURAL HISTORY July/August 2005 Her newborn wobbling at her heels, Meanwhile NLCP, our project to cousins to assist with the squealing in- Gift walked down the paths in our assist villagers, had grown. We fants, no sisters to help protect their off- camp; they looked more like two small were now ofiering aid and education spring. Our aerial counts showed that sisters than mother and offspring. to approximately 20,000 Zambians in even though the poaching had stopped, remote villages near the park. And to the elephant density was not increas- Gift was not a good mother For one our great reUef, in 1996, we recorded ing, possibly on account of high calf thing, of course, she was very no elephants shot in NLNP. mortality and the protracted reproduc- young. But since she had not been raised But because the North Luangwa tive cycle. It will probably take many in a family unit, she also had no expe- elephants had been harassed and killed years for the numbers to recover. rience with the frequent touching and for so long, many of them were stiU gentle care that are part of normal ele- wary of people. The best way to ob- the time Gift was sixteen years phant social life. Gift rarely reached her serve them was from the heUcopter Byold—an age when, under normal trunk to her calf and sometimes hard- purchased by the NLCP. Two or three circumstances, she would have been ly seemed to notice her. hi the first times a week we took off in the chop- giving birth to her first calf—she had weeks of life, a calf stays close to its per and soared over the radio-coUared three calves ofher own and one grand- mother, sometimes leaning against her elephants as they moved over the lush calf. The grandcalf (Georgia's calf) large leg as ifit were a tree trunk. When plains or riverine forests. We stayed eventually died, but this small family it is a tew months old, it begins to ex- high enough to keep from disturbing unit, founded by an "ivory orphan,"

Poaching has cut the average size of the elephant family unit in half

plore farther away, but if it strays too far, them, and monitored the new infants was making a comeback. Like a single the mother or another female will fol- born into each family. We also contin- mother in a disrupted human family, low it. Not so with Gift and Georgia. ued to determine the age of the pop- she was making the best of a bad situ- One morning when Gift was feed- ulation by measuring footprints. But ation without relatives, without cul- ing on marula fruits in camp, Georgia, we had stiU not solved the mystery of ture, without much social support. But now about three months old, wandered why each family unit always included she was still making a go of it. away from her mother. Gift walked more infants than adult females. The disruption we have seen in ele- quickly and silently in the opposite di- One morning we watched a young phant social behavior in North Luang- rection, toward some large marula trees female, about the same age as Gift, wa is mirrored in other populations of about forty yards away. Moving her suckling a newborn. Mark said into African elephants on the continent. trunk along the ground like a vacuum the radio intercom, "That's it. Gift They too are facing decreased numbers cleaner, she searched for fruits until she giving birth so young is not a fluke. of matriarchs, the breakdown of fami- was out of sight of her calf The adults are dead, so the adolescents ly units, and a shift in sex ratio favor- Suddenly Georgia looked up and are giving birth!" ing females. But Gift's abiHties as a fam- could not see her mother. SqueaUng We flew a beeUne back to camp, and ily leader, which have improved as her loudly she dashed around camp, her ht- revisited our data. In 70 percent of the family has grown, is her Httle herd's tle legs pumping and her trunk wrig- family units there were not enough foothold on the future, and perhaps the gUng. She trotted up to us, stared at us adult females to account for the num- best hope for the return of the great for a few seconds, and then ran toward ber of infants. But there were plenty of herds of yesterday. the office cottage in the opposite di- adolescent females that could have been rection from her mother. We backed the mothers. We started making de- Deua and Mark Owens have conducted up so that we could see Gift. The young tailed observations ofthese family units. research and established conservation projects on mother continued to feed on marula And, sure enough, in the absence of endangered species in Africa for twenty-three years. From 1986 until 1997 the Oweuses de- fruits, completely ignoring the shrill adults, females in North Luangwa be- veloped the North Luangwa Consen>ation Pro- cries of her calf. We fought the urge to tween eight and a half and fourteen ject in Zambia, which was financed by the chase Georgia toward her mother, for years old were accounting for 48 per- Owens Foundation for Wildlife Conservation fear of making matters worse. cent of all births. On their own or in and the Frankfurt Zoological Society. Tlie pro- Finally, Gift walked into view and small faixdly units of only two or three ject's pillage programs continue today under the Georgia saw her. calf trotted to elephants, these "teenage" mothers The direction of Zambians. The Owenses are the her mother's side, and stayed very near were slowly, haltingly fostering the next authors of numerous articles and the best-sell- her until they both ambled out ofcamp generation. They had no old matriarchs ing books Cry of the Kalahari and The Eye several minutes later. to lead them, almost no aunts or female of the Elephant.

July/August 2005 NATURAL HISTORY 25 JULY/AUGUST 2005 Cold Fire

In Antarctica's Dy]^^^^ the deep chambers and' conduits

that poured hot lava onto the surface

are exposed as tiowhere else on Earth

Edmond A. Mathez

jTSi^

exotic, and starkly Normally one would think nothing of pouring gion IS surely among the most remote, ice and snow- Scotch whiskey over a few chunks ofice. But this beautiful corners of the planet. In spite of the Taylor, and oth- ice was more than 18,000 years old! It came from that blanket the rest ofAntarctica, Wright, the most wa- the Taylor Glacier, an enormous river of ice flowing off er parts of the Dry Valleys are deserts, among the polar ice cap into Antarctica's Taylor Valley. The wall terless places on Earth. past decade. Marsh has been studying a labyrinth of the glacier is marked by a pair of thin, brownish layers For the exposed in the walls of the Dry of volcanic ash, each containing mineral grains that have of basaltic rock spectacularly is of dikes (sheetlike bodies been dated by radioisotope decay. The lower layer is 18,000 Valleys. The labyrinth made up strata) and sUls (bodies par- years old, and since our ice came from below it, we knew ofrock that cross the surrounding fine-grained black rock, is the the ice must be older than that. allel to the strata). Basalt, a on Earth. It forms when the The "we" in this band of Scotch drinkers included me most common igneous rock resulting mag- and t^venty-four other geologists. At the behest of Bruce Earth's upper mande partially melts, and the it can soUdify rapidly, either within Marsh, a geologist at Johns Hopkins University, and with ma rises to places where erupting lava. the support of the U.S. National Science Foundation, we the crust, as dikes and sills, or at the surface, as Valleys are the remnants had assembled in Wright Valley, one of the McMurdo Dry The dikes and sills of the Dry system through which magma Valleys of Antarctica—or simply, the Dry Valleys. The re- of a kind of plumbing

July/August 2005 26 ! NATURAL HISTORY worked its way to the surface in a series of eruptions about the valleys' dolerites as such. Dolerite is basaltic magma that

180 milHon years ago. Volcanic plumbing systems are rarely soHdifies rapidly in sills and dikes near the surface. exposed at the surface. The reason is simply that around The dikes and siUs bear on several questions geologists ask. active volcanoes, lava covers everything. Even at old, inac- One of them is why volcanoes commonly erupt lavas that tive volcanoes that have been deeply dissected by erosion, vai7 so widely in composition—a major factor in creating geologists commonly see only the interior of the volcanic the planet's surface. Marsh had chosen to study the Ferrar edifice, not the structure of the rocks below. dolerites because they are quite variable in composition and Exposed to view in various parts of the Dry Valleys, how- also extremely well exposed in the valley walls. Now he had ever, is a vertical sUce of the dikes and siUs immediately be- assembled a group ofgeologists, all experts in the physics and neath the lavas, which cuts across layers of rock two and a chemistry of magmatic systems, to share insights, help dis- halfmiles thick. Hence along the vaUey waUs, geologists can cover the reasons for the compositional diversity, and use the see much deeper into the volcanic plumbing than they can lessons learned in Antarctica to understand complex bodies almost anywhere else. Taken together, the dikes and siUs of of rock elsewhere in the world. the Dry Valleys are known as the Ferrar dolerites, after Hart- Sipping Scotch in our isolated camp, though, we were ley Ferrar, the geologist who, as a member of Robert F. fascinated not only by the rocks, but also by the enormous Scott's 1901—1904 Discovery Expedition, first recognized scale and ahen nature of our surroundings. The Dry Valleys

July/August 2005 NATURAL HISTORY 27 150°E

leys may act somewhat like icy features discovered on Mars, and the bacteria that occur in the ice and

saline lakes may resemble extraterrestrial Hfe, if it ex- ists. So let us take a moment to wander through the hyperdry, hypercold landscape. A . nent, with an area far larger than that ofthe United States (5.25 77.25°S million versus 3.5 million square miles). Obscured by the continent's ice cover, the Transantarc- tic Mountains divide Antarctica

into two parts [see map at left]. The

major part of the continent lies in the Eastern Hemisphere, on one

side of the mountains, where it is apparently made up of ancient, crystalline bedrock. Most of that

rock Hes above sea level and is covered by the East Antarctic Ice Sheet, a body of some 6 million cubic miles of ice. On the other

side of the mountains is the much smaller (0.8-niiIlion-cubic-mile) West Antarctic Ice Sheet, which rests on an ancient bedrock that

would be submerged, were it not topped by ice. Immediately to the east of the 160°E Transantarctic Mountains, the Dry Valleys extend from the po- miles lar plateau seaward toward Mc- Shaped like a set of fingers, the Dry Valleys extend toward Murdo Sound, an arm of the Ross Sea, roughly six- the open sea. Only Taylor Valley reaches the sea, however. ty miles away. The reason the valleys exist at all is The valleys' extreme aridity is a consequence of their posi- that the Transantarctic Mountains dam the East tion flanking the Transantarctic Mountains and the polar Antarctic Ice Sheet, largely preventing it from flow- plateau. Cold, dense, dry air masses form on the plateau and tumble down the valleys with the prevailing wind. As the air ing toward the sea.

descends, it warms and thereby expands its ability to hold At the floor of the valleys the average annual tem- moisture, carrying off virtually every bit of water in its path. perature is minus four degrees Fahrenheit (minus The Transantarctic Mountains also hold back the seaward twenty degrees Celsius), and the annual snowfall movement of the East Antarctic Ice Sheet, keeping the val- amounts to less than half an inch of equivalent Uquid leys largely free of ice. water. The valleys are kept both cold and dry by cold, dense air masses that form on the polar plateau and feature rivers that stay bone-dry except for summer then tumble down the valleys in what are called kata- trickles that flow inland to frozen lakes many times batic winds, displacing warmer air over McMurdo

saltier than seawater; glaciers whose surfaces sublime Sound. As the air descends from the plateau, it warms,

(turn from solid ice directly into water vapor) but do amplifying its ability' to evaporate moisture. Summer,

not melt; inicrobial communities that Uve in bubbles naturally, is the "warm" season, with temperatures of Hquid water locked within subliming lake ice for near freezing. In Wright Valley, the summer melt- hundreds to thousands of years. The region opens a water collects in the Onyx River, the largest "river" window into igneous geology, as well as into how in Antarctica—a rather highflown description for the Antarctic ice sheet responded to cUmate fluctu- what is hardly more than a trickle in the Antarctic

ations in the past, and how it may respond in the fu- summer and nonexistent the rest of the year. ture. Finally, the glaciers impinging on the Dry Val- The lakes scattered throughout the valleys are

28 NATURAL HISTORY July/August 2005 I perennially covered by ice, which is typically ten feet ice, leaving, within the glaciers, bowl-Uke pools or more thick. They would probably freeze com- called cryoconite holes. Because the summer air pletely were it not for the summer sun that warms temperature is commonly stiU below freezing, the them and the ice cover that insulates them during "holes" remain sealed by ice. Nevertheless, the wa- the winter. In fact, the bottom of Lake Vanda, in the ter collects in small, coalescing passageways and heart of Wright Valley, is 226 feet deep; there, the eventually trickles out of each glacier. water temperature is a comfortable seventy-nine degrees F (twenty-six degrees C). Where liquid water does occur, life finds a toe- Despite being fed by meltwater, most of the lakes hold. The cryoconite holes, encased in ice, are extremely salty. For example, the sahnity of Lake host communities of bacteria. The same organisms

Vida, in Victoria Valley, is seven times that of sea- also occur in the lakes of the Dry Valleys, where they water. The basic reason for the high saUnity is that form algal mats. Sometimes pieces of the mats be- the lakes are extremely old—old enough for salt to come encased in ice that migrates upward as the top have built up, even though the waters that enter of the ice subHmes. The process takes a long time, the lakes bring only minuscule amounts. Funda- and microbial mats as old as 2,800 years have been mentally, the lakes lose water as the top of each lake's identified. Besides bacteria, Hfe is limited to a few ice cover subHmes and is lost to the dry atmosphere. lonesome Hchens, which grow on protected rock sur-

The lost ice is replaced by new ice forming at the faces, and to several species of microscopic worms bottom of the ice cover. In the process, salt gets left known as nematodes, which live in the soil in the few behind in the Uquid water. places that become damp in summer.

The glaciers of the Dry Valleys are as exotic as the Since nearly all of Antarctica is covered by ice, lakes. The glaciers are said to be "cold-based," which means that, unhke nearly all glaciers outside Antarctica, their bottoms are frozen. That property makes them act idiosyncratically. In places such as Greenland or the high peaks of the Alps, "wet-based" glaciers scrape the bedrock over which they flow, picking up substantial quantities of rocky debris. Where the ice melts, the debris accumulates in ridgeUke piles known as moraines. Cold-based glaciers, by contrast, flow mainly by deformation; the ice itselfflows hke putty, pushed by its own inexorable weight. These glaciers pick up very Httle debris, cause Utde erosion, and leave only small moraines. Cold-based glaciers even look different. Instead of being thick rivers of ice fuU of crevasses, the glaciers within the Dry Valleys are flat and rather smooth; some are even shaped Uke pancakes. They, too, lose their ice mostly by subHmation, so Uttle or no meltwater issues from them. The enormous riverlike gla- Wall in a side canyon of upper Wright Valley exposes two dark bands of rock: at the ciers, such as the Taylor Glacier, base is a talus slope made of those rocks. Each band is a basaltic sill, formed when that enter the heads of the major magma intruded into and then solidified between the layers of the surrounding valleys do provide some Uquid wa- rock—in this instance, light-colored Beacon sandstone. The topmost dark body cap- ter. In summer they absorb solar ping the cliff face is the Mount Fleming Sill; below that is the Asgard Sill, here about heat, which melts the subsurface 800 feet thick. To the right is Wright Upper Glacier.

July/August 2005 NATURAL HISTORY 29 —

carved sinuous valleys with flat floors and steep semi- circular walls.

The Antarctic ice cap began to form much later than the valleys did, about 34 million years ago. The fundamental cause was the opening of the Drake Pas- sage, the part ofthe Earth's great Southern Ocean that separates Antarctica from South America. The newly circumpolar ocean established a circumpolar current that blocks the southerly flow ofwarm water and thermally isolates Antarctica from the rest ofthe world.

In contrast to the Arctic, which is highly sensitive to global climate change, the Antarctic cHmate has remained relatively stable for millions of years. Early on, glaciers did cover much of the Dry Val- leys. The glacier traces are hard to miss: rock surfaces have been scoured smooth, and rocky, gravelly debris

known as glacial till has been scattered throughout the high valleys. But by about 14 million years ago, the glaciers—except for the small, cold-based glaciers of today—had largely disappeared from the valleys. How do geologists know? On some of the surfaces high above the valley floors, deUcate volcanic ash deposits,

some as old as 13.6 million years, lie just beneath the Geologic strata exposed at one or another part of the Dry desert pavement—the loose rock and gravel too heavy Valley walls and floors include four basaltic sills (dark blue), for the wind to have blown away. Those regions of as shown in the schematic diagram, based on a model by the Dry Valleys have remained hyperdry, hypercold, Bruce Marsh of Johns Hopkins University. Tongue-shaped

regions of basalt (gray) rich in crystals of the mineral or- and glacier-free, at least since the ash fell.

thopyroxene protrude into the sills from basaltic dikes, or vertical intrusions of once-liquid rock, that cross the inter- don't mean to suggest that nothing has happened vening rock layers. The topmost stratum is made up of I "recently." Low parts of the valleys were flooded basaltic lava that erupted, still molten, after ascending by the sea: nine-rmllion-year-old sediments, typical through the labyrinth beneath. of the sediments at the bottoms of fjords, remain in one might reasonably suppose that the Dry Valleys the floor ofWright Valley. Similar deposits, aged be- were simply carved by glaciers that overtopped tween 6 million and 3.4 million years, occur in Tay- the Transantarctic Mountains. Unlike rivers, lor Valley. Since then, the region has been uplifted which tend to cut valleys that are V-shaped in and so the major valley floors are now mostly a few cross-section, glaciers characteristically carve a U hundred feet above sea level. There was also a peri-

(think of California's Yosemite Valley) . The walls od ofglacial advance, about 3 million years ago, when and floor of the lower reaches of the Dry Valleys the Taylor and Wright glaciers expanded into the

are indeed shaped like a U, but to the practiced lower parts of their valleys and left deposits of tiU as eye the U looks too wide and too shallow to have their calling cards. At various times, sea ice has also been solely glacial. invaded the lower valleys. In brief periods of relative The most telling evidence of how the valleys did warmth, glacial meltwater accumulated behind this

form occurs at high elevations, where geologists have ice to form small, temporary lakes. Their sites are discovered reinnants of flat surfaces interrupted by marked today by local beds of sediment in the valley steep-waJled valleys. The latter valleys appear to be floors. Yet none ofthese events fundamentally altered relics of river erosion 55 iTullion years ago, when the the landscape; the vista we gaze on today has remained climate was semiarid and Antarctica had no ice. In largely unchanged for at least 14 million years.

those days, in a sense, Antarctica did not exist at all. In today's valleys, the Ferrar dolerites occupy four It was stOl attached to Australia as part of a larger con- massive siUs, each between 330 and 1,150 feet thick,

tinent known as Gondwana. There are places on interconnected by a series of dikes [see illustration on

Earth today that may bear a close resemblance to the this page]. The intricacy of the array is accompanied

Antarctic landform back then. One of them is the by a wide variation in the composition of the Colorado Plateau of southern Utah and northern rocks—a variation presumably related to the way Arizona, where seasonal rivers and streams have the magma solidified. Unlike water, which freezes

30 NATURAL HISTORY July/August 2005 —

«*»

at a single temperature, magnia freezes over a temperature interval. Most basaltic magmas are completely molten at 2,200 degrees F (1,200 degrees C) and do not become completely solid untU the temperature tails to about 1,650 degrees F (900 degrees

C) . As the magma cools between those two temperatures, different minerals crystallize, or freeze out, at different temperatures. These minerals are not the same in composition as the magma itself. Therefore, as crystals form and sink or otherwise separate from the magma, the composition of the residual magma changes. Tongue of orthopyroxene-rich basalt, em- In a cooling basaltic magma, the first bedded in the Basement Sill, is exposed in mineral to crystallize is usually oUvine, Wright Valley; its position is shown in a magnesium silicate (MgiSiOJ that al- schematic diagram at right. The tongue has so includes some dissolved iron. In the been eroded by wind and is now covered with sand that makes it look smooth. The case of the Ferrar dolerites, the first to reddish striations above and below the fireeze out was orthopyroxene (MgSiO, Basement Sill are basaltic dikes that predate with about 15 percent dissolved iron). the sill. When the sill intruded, it cut Because orthopyroxene—and, for that through those dikes. matter, olivine—both have a higher proportion ofmagnesium than magma does, the magnesium content of the residual magma suspension by the upward-moving magma and falls as these minerals crystaUize. As cooling contin- forced toward the center of the flowing slurry. ues, plagioclase (a mixture of two kinds of aluminum When the flow of magma intruded between lay- silicates) and the pyroxene mineral augite (a magne- ers of rock as a siU, the Hquid began to solidify at the sium silicate mixed with some iron) form. sill margins. The "soUdification front" then pro- ceeded inward as the basalt continued cooling. The distribution of orthopyroxene proved to be Meanwhile, the suspended orthopyroxene crystals, our most telling clue for understanding the Fer- most of which were now near the center of the siU, rar dolerites. Looking closely at the rocks, we could slowly settled into the lower part of the magma in see clear differences among the siUs. Some are made which they were suspended. When the solidifica- up of dense, black, homogeneous basalt, with no vis- tion front moved entirely through the siU, it pre- ible mineral grains. Others have varying abundances served the tongue-shaped distributions of orthopy- of orthopyroxene crystals suspended in otherwise roxene crystals we see today in the valley walls. fme-grained rock. In consequence, the rock varies Elsewhere in the world, geologists have studied from 3 percent to 12 percent magnesium, depending vast bodies of well-layered igneous rocks. Some of entirely on the proportion of orthopyroxene. those rocks hold important deposits of metals such Marsh and his students have meticulously mapped as platinum, for reasons that may be related to the those proportions. The maps show that orthopyrox- rock-layering process. The layering has thus en- ene crystals are distributed within the siHs in great gaged the attentions of several generations of earth tongues, sometimes extending for tens of miles along scientists, who continue to wonder not only about the sills. The orthopyroxene-rich tongues are thick- ore deposits, but also about the larger lessons the est—occupying perhaps half the height of a sill layered rocks may hold. In the Dry Valleys of where the siUs appear to have fiUed from their feeder Antarctica, where the Ferrar dolerites solidified dikes, and they thin from the filling points toward rapidly, geologists have caught the layering process the more distant parts of the siUs. in the act. Thanks to the fortuitous circumstances Given the high melting point of orthopyroxene, that keep the landscape free of ice, the Dry Valleys its distribution into tongues suggests it froze out of are among the planet's best places to study how the melt deep in magma chambers, before it reached various kinds of rocks form, and even how the the sills. Crystals of the mineral were then carried in deep Earth organizes itself. D

July/August 2005 NATURAL HISTORY 31 rn

In the Heat of the Night

An assassin bug's sensory journey

By Graciela Floras

rural areas of Latin America, adobe houses with thatched roots are Infixtures of the landscape. The houses are crisscrossed by crevices that serve as hideouts for insects. In the evenings, as the sun goes down, masses of intertwined heads, legs, and antennae start to disentangle. One by one, the insects come out and start their nighdy search for blood. They are called kissing bugs or assassin bugs in English, but in Latin America they have many regional names. In my home country' ot Argenrina, we call them vinchucas, a word derived from Quechua (a family of languages dating back

to the Incan Empire), which means "those who let themselves fall." These insects are bloodsuckers, and when searching tor a blood meal they honor their Quechuan name: because they are such bad fliers, they let themselves drop from walls and ceilings. Once on the floor, or ^^•hile crawhng down the walls, the insects skiUfuUy navigate the intricate micro- landscape of odors, shadows, and temperatures they encounter. When a vinchuca fmds a host—a dog, say, or a sleeping human—it s\\'iftly locates a blood vessel. Next, it extends its proboscis, a beak neatly folded under

its head, and pierces the skin of its victim. As it feeds, the bug injects a cocktail of analgesics, anticoagulants, and vasodilators that help the blood flow smoothly and painlessly.

Slowly, the vinchuca grows, as Charles Darvwn described with disgust v^\*-:. after being attacked by one in Argentina, from "flat as a wafer to a globu-

lar form," as it becomes "bloated with blood." While still feeding, the in-

sect releases urine and feces on the skin of the host, making room in its abdomen for the enormous amount of incoining blood. [See photographs

oi; page 34.] The vinchucas e.xcretions can harbor a protozoan known as Tr)'patiosoma avzi—the cause of Chagas' disease. The T. cnizi parasites come, in turn, from another animal, and get sucked up when the insect feeds on that infected host. Thus the \anchuca acts as a carrier, or vector, for 77 cnizi. When a healthy bite \'ictim scratches at a vinchuca wound, any T cnizi parasites in the droppings can slide inside the vdcrim's open skin, and eventually move through the bloodstream to colonize heart muscle and other bodv tissues. mmm rM^^m^igti^gimmmi^imm^ ^ssssa..

Symptoms of Chagas' disease vary dramatically, particularly in the early stages. Some people never develop side effects, whereas others experience fever, rashes, and fatigue a few weeks after being bitten. About a quarter of the infected population suffer from serious heart or digestive disorders, which only develop decades after the initial infection. Of the some 20 million people in Latin America now infected with T. cntzi, about 50,000 die every year. Those figures make Chagas' disease one ofthe most widespread and economically devastating tropical diseases in the world.

And tor poor countries, in which substandard housing is widespread, the

total economic loss due to Chagas' disease is staggering.

Vinchucas are relatively unknown in big cities, simply because urban A housing does not offer them appropriate refuges. As a cit>' dweller

myselt, I did not encounter a vinchuca until I became a graduate student in the Laboratory ot Insect Physiologs', at the Universit}' of Buenos Aires.

There I was part ot a team trying to answer some of the many outstand-

ing questions about vinchucas. As my colleagues and I immersed our- selves in the study of the insect and pooled our results, we were able to

reconstruct the insect's sensory trip from its refuge to its host. In common usage, the term "\dnchuca" can refer to many species. We

concentrated on one, Triatoiiia iiifestaiis, which thrives in the arid north of Argentina and Uves almost exclusively in human dwellings. When we start-

ed our research, the behavior of T iiifestaiis was not well understood. The director of our laboratory, Claudio R. Lazzari, had surveyed the species' behaviors during his own graduate work, with the insect physiologist Josue A. Nunez, also of the University of Buenos Aires. From Lazzari, Niiiiez, and .H- a few other insect physi- m ologists, we knew that

T. iiifestaiis could home in on an animal's blood vessel even in a pitch- dark room. But we -*i did not know how it accomplished the task. Odors, chemicals, and

heat all clearly played a

Vinchucas spend their days

crowded together in refuges such as

the crad

~~The interior of one such house is shown im pressionistically on these two pages. At dusk, the internal clocks of the vinchucas set the insects on their nightly search for a blood meal. —~~

role, but we were clueless about exactly how the their high temperatures help disperse chemicals by insects exploited that information. So we divvied creating local convection currents. up the various aspects of the vinchucas' biology and One of the best indicators that a good source of

behavior among the members of our team. I fo- blood is nearby is a gas that, to us, is odorless: car- cused on the thermal sense—to me, the most fas- bon dioxide. Most blood-sucking insects, including cinating sense of all. mosquitoes and vinchucas, however, can smeU car- By day, the vinchuca remains in a sleeplike state bon dioxide, and they rely on that cue in their search

known as akinesis. At dusk, however, the insect is for a host. My colleagues discovered that an inter- activated by an internal biological clock, which reg- nal clock controls the sensitivity ofvinchucas to car-

~~ulates most of its behaviors. The newly awakened bon dioxide. It turns out that the insect's sensitivity~~

is highest in the first hours of the night, at the start of their journey. Vinchucas have olfactory receptors ^S\ for dozens of other scent molecules as well as for carbon dioxide. Upon detecting a promising odor,

~~the vinchuca adopts a new tactic: it travels "upwind," against any local~~

~~currents of air, to get closer to the~~

source. As it follows the current, the Vinchuca (Rhodnius prolixus), the species first studied in the 1920s insect gauges its direction with for its response to heat, feeds on a human host. The insect starts motion-sensitive hairs, as out "thin as a wafer, " as Charles Darwin noted, left, but balloons known

in size and empties its bowels as it fills with blood, right. mechanoreceptors, which are abundant on the antennae. In a new state vinchuca raises its antennae—its sensing instru- of alert, the vinchuca closes in on its intended host, ments—and, usually, grooms them: a mesmerizing and as it does, it enters an undulating landscape process. Standing steady on its four rear legs, the in- of temperatures.

sect lifts both front legs and unhurriedly draws first one antenna, then the other, through small combs For all the vinchuca's sensitivity to smeU and touch, on the inner sides of the two front legs. Now it is heat is the ultimate stimulus that prompts it to ready to go. bite. We devised a way to demonstrate that behavior As the last hints of daylight disappear, the insect in the laboratory. We heated a piece of metal to the starts randomly walking, moving its antennae surface temperature of a warm-blooded animal smoothly up, down, forward and backward. Every about ninety degrees Fahrenheit (thirty-two degrees so often, though, the insect pauses, and the smooth, Celsius)—and brought the metal within range of a sweeping antenna movements become jerky, re- vinchuca's proboscis. Immediately the vinchuca ex-

~~sembHng the old semaphore method of flag signal- tended its proboscis and repeatedly tried to bite the~~

~~ing. The vinchuca is sampUng the air. metal. Furthermore, when we cooled the metal to The vinchucas antennae are remarkable struc- below ninety degrees Fahrenheit, no other stimulus~~

~~tures. Less than a third of an inch long in adults and we presented could induce the vinchuca to extend its~~

~~even shorter in the larvae, the antenna is the seat of proboscis. Even if the insect hadn't eaten for forty~~

~~thousands of so-called sensiUa, the insect's sense or- days, we could not get it to bite a cool surface.~~

~~gans [see illustration on opposite page] . Each sensillum My colleagues were able to come up with only~~

~~is a sensory unit made up of one or more neurons, one way to circumvent the vinchuca's virtually au- plus supporting cells that nourish them. The sen- tomatic response. They placed a miniature copper~~

silla endow the insect with senses ofheat, smell, and rod, warmed to the temperature of a warm-blood- touch. Taken together, the antennae and their sen- ed animal, near the vinchucas' antennae, and tricked

siUa are the insect s window on the external world. the insects into drinking cold blood. It is hard to imagine a clearer, simpler demonstration ot how The wandering vinchuca, antennae waving, has important thermal sensiUa are to the insects' feed- entered an odor plume. Mists of molecules ing routine. Odors from a potential host initiaUy

bump into the insect. Some of the molecules pen- attract vinchucas, but heat is the only stimulus both etrate the insect's cuticle through minute pores and necessary and sufficient to get them to bite. reach the olfactory sensiUa just beneath. Warm- A current of warm air has now reached the in- blooded animals are an endless source of odors, and sect's sweeping antennae. As the thermal sensiUa

34 NATURAL HISTORY July/August 2005 absorb the heat, they warm up. Vinchucas, like Vinchucas are also unusual in that their antenna car- most animals, can detect heat through conduction ry a kind of sensiUum observed in only a few other or through rising air currents. Amazingly, though, blood-sucking insects: the "cave organ." Since its dis- the insects can also sense radiant heat—known as covery in the 1950s, the function of the organ has infrared radiation. been a mysteiy. It is a pit (hence its name) lined with Lazzari and Nuiiez discovered that capability hundreds of thin, short hairs that have no pores. Each when they placed windows, impenetrable to in- antenna, moreover, has only one cave organ, in sharp frared radiation, between the insects and a source of contrast with other kinds of sensilla that number in heat—^which was, again, a miniature metal rod at the hundreds, Lazzari showed that the cave organ re- the right temperature. All the vinchucas' usual re- sponds to heat but not to odors, and suggested that it sponses to heat disappeared, but were duly restored might be acting as an infrared receptor. But there is when the experimenters replaced the infrared- still no clear-cut evidence supporting the hypothesis. opaque window with a window transparent to infrared rays. The insects could detect temperature Studying the vinchuca's response to heat requires changes as small as 0.0072 degree F (0.004 degree a love for the minuscule—and good craftsman- C)—which makes them among the most thermally ship as well. In our laboratory, everyone created the sensitive animals known. Only a few other animal tools he or she needed. That rule was mainly driven species are known to be sensitive to radiant heat, in- by the bug-size devices that had to be custom-made cluding boas, pit vipers, pythons, and the jewel bee- for each experiment. But it also stemmed from a trade (Melanophila aaimiiiata)—an insect able to detect dition in entomology, inherited from such early in- forest fires from nearly fifty miles away. vestigators as the EngUsh entomologist Vincent B. Wigglesworth. Wigglesworth began his studies on Thousands of sensilla cover the vinchuca's antennae: anothervinchuca vector of Chagas' disease, Rhodiiius mechanoreceptors (a) give the insect a sense of "touch;" prolixus, in the 1920s, and became the first to study thermoreceptors (b) respond to heat; chemoreceptors (c) bind to scent molecules; and the solitary cave organ (d)—one its response to heat. He soon encountered a problem per antenna—may help the insect detect infrared radiation. that many others have faced as well: As an insect walks,

~~July/August 2005 NATURAL HISTORY 35 —~~

~~Experimental apparatus for testing a v/nchuca's responses to heat is shown schematically. The~~

~~insect was tethered to a stand and allowed to walk in place, while it held on to a rounded, tetrahedral Styrofoam object called a spangenglobus. Warm metal plates of equal size and tempera-~~

~~ture were placed at various distances (A, B, C), and smaller plates, subtending the same angles as the plates at distances B and C, were placed at distance A (pink and yellow rectangles). The~~

~~insect spread or closed its antennae as the plates varied in distance or size, just as if it were~~

~~"measuring" the angle of each plate from its point of view. Thus, with an independent estimate~~

~~of distance, the vinchuca could also estimate the true size of its potential host.~~

~~the amount of heat reaching it constantly changes. that on the left, and notes which way the insect turns,~~

~~How, then, can the experimenter maintain a con- the animal s behaviors can be studied in detail.~~

~~stant distance between the insect and the heat source, 1 inherited my spangenglobuses from Lazzari: ten~~

~~and thereby control for the heat reaching the insect, hand-carved hoUow Styrofoam balls. I guarded the~~

without stopping the insect from walking? little treasures with zeal and kept them together with The problem was ingeniously solved more than half ten custom-made acrylic boxes, ten diminutive cop- a century ago. The German behavioral biologists per pincers, a miniature brush made ofmy own hair, Bernhard Hassenstein and Werner Reichardt devised and a few sohd aluminum plates that served as heat

the celebrated—^in the world ofentomologists span- sources. With this basic homemade tool kit I stud- genglobus. The device is essentially a miniature tetra- ied the vinchucas' responses to heat. We later ac- hedron that has been "inflated" into a more nearly quired more sophisticated gadgets, but the first ex- spherical shape about three quarters of an inch in di- periments, the ones conducted with the most prim-

ameter. The tetrahedral framework is made of a light itive tools, were by far the most interesting. material such as balsa wood or, in our case, Styrofoam. The back of the insect, in mrn, is glued to a rod that With the spangenglobus, Lazzari had tested the suspends the insect directly beneath a frxed frame. Be- behavior of blinded vinchucas—their eyes cause the spangenglobus weighs about the same as the had been covered over with paint—when he con- insect does, the insect can grab the spangenglobus with fronted them with pairs of metal plates at different

its legs and walk, just as ifit were walking upside down temperatures. He found that the insects walked to- and gripping a ceiling with enough force to support ward temperatures close to that of a warm-blood-

~~its own weight. To the insect, then, holding on to the ed animal, away from plates that were hotter, and~~

~~surface of the spangenglobus as it walks is indistin- were unaffected by the ones at room temperature.~~

guishable from walking upside down on a soUd sur- This result might seem obvious, but it is not. It has face. Like Lewis Carroll's Red Queen, the insect walks an important imphcation: the insects can estimate and walks, only to stay in the same place. the temperature of a distant object. Furthermore, in The tetrahedral shape also has a clever purpose. Be- Lazzari's experiments the vinchucas never raised cause three edges come together at each vertex, when- their proboscises in an attempt to bite the warm

~~ever the insect walks up to a vertex, it faces a choice metal plate: they "knew" it wasn't close enough,~~

~~of two ways to proceed, left or right. If the experi- even though their eyes \vere covered. menter presents a stimulus on the right different fi^om In another experiment, this time with unre-~~

~~36 NATURAL HrsTORY July/August 2005 a~~

~~strained, freely walking—^but still blind—vinchucas, the insect's point of view—regardless of the actual~~

I observed that once the insects reached the heat size or distance of the source. In other words, when source, they repeatedly tried to bite and pierce the two plates subtended the same angle—one big and metal; they all extended their proboscises when they far away, the other small and nearby—the antennae were about halfan inch from the source, even though also made the same angle with each other. The pieces they could not see it. Did that imply that they could of the thermal puzzle were beginning to fall into estimate distance as well as temperature? Abundant place: the variable of size might be accounted for. evidence suggested they could; it was time to ask how. Let's go back to the vinchuca once more and re-

To answer that question, think about what hap- construct the last part of its journey. The insect, at- pens to the thermal sensilla. When confi^onted with tracted to a host by its smell, enters the thennal do- a heat source, the sensilla receive a given amount of main. Close enough to perceive the host's heat heat, which fires neurons. But that information, by through thermal receptors, it turns and faces the itself is not enough to discriminate sources at differ- source of heat. Scanning the air, it follows the edges ent temperatures, because a distant—or small—hot of the heat source with its antennae, whose position source could produce the same local warrmng as a is being closely monitored by mechanoreceptor hairs. closer—or larger—cool source. Thermal sensilla These hairs bend when the antennae move, and re- alone cannot distinguish those two conditions, but port the antenna position to processing centers in the vinchucas certainly can. brain. The insect thus estimates the apparent area, or The insects might be recognizing two character- size, of the heat source. istics ofthe heat source: distance and size, and "com- The amount of heat from a given source increas- puting" a third characteristic, its actual surface tein- es as the vinchuca gets closer to that source, but the perature. Vinchucas could gauge distance—we had increase is not proportional to the distance. Instead ample evidence of that. But I the heat is inversely propor- w^as determined to find out Spreading their antennae tional to the square of the dis- about their ability to discern tance. Ifthe vinchuca walks to helps vinchucas estimate size. Ifthey could estimate the within half its initial distance first two of these variables, the size of a host. from the heat source, the in- then, given the basic physical sect gets four rimes as much and geometric circumstances, maybe they could heat as it got at first; if it takes a few more steps, to a

~~"calculate" the third. quarter of its initial distance, the heat increases to six-~~

teen times its initial level. We think such rapid changes The antenna movements of a walking vinchu- in heat play a key role for the insect in determining ca, which I knew in great detail, gave me an its position with respect to the heat source. For ex- idea. Confronted with a warm source—or with the ample, a vinchuca might measure the amount of heat hand of the experimenter, for that matter— received in two different parts of its body, say, the vinchuca walks toward the potential blood meal, head and the rear end. By comparing the amount of opening and closing its antenna. Perhaps those an- heat received at those two points, it could estimate tenna movements, which expose the thermal re- the distance to the heat source and thus assign a val- ceptors to the heat source, were also enabling the ue to the second variable. vinchuca to estimate the size of the source. Knowing the area and the distance, the vinchuca

I devised two tests for my hypothesis. In the first, I could "derive" the third, and crucial, variable: the put heat sources ofvarious size at a frxed distance from actual temperature of the heat source. If it fell in the the insect; in the second, I put a single heat source at known range of temperatures of a warm-blooded various distances [see illustration on opposite page]. In animal, the vinchuca might as well try for a meal. both experiments, I filmed the vinchucas on the span- Thus ends a bug's trip from its refuge to a host, a genglobus as they reacted to heat, and digitized the trip aided by amazing sensory instruments. It is a positions of the antennae every second. From the journey repeated endlessly by millions of vinchucas filmed positions I determined the angles between the every evening, across Latin America. In spite of the antennae and compared them from test to test. To my vinchuca's superior homing skills, this journey amazement, I found that the antenna aperture would not be possible without a proper refuge dur- changed with both the size of the source and the dis- ing the day. And yet, in many countries, the straight- tance between the source and the insect. forward approach of improving housing condi-

When I plotted the angular values, it became clear tions—fdhng in nooks and crannies—remains only that the position of the antennae simply, and consis- a dream, and the insects continue to have free reign tently, followed the apparent size of the source from on their nightly forays. D

~~July/August 2005 NATURAL HISTORY 37 Unhappy Trails~~

~~Forensic examination of ancient remains sheds new on the emergence of Florida's Seminole Indians.~~

~~By Christopher M. Stojanowski~~

Onjanuary 30, 1838, the Seminole war hero Following a period of uneasy peace, warfare had Osceola died of malaria while in captivity erupted again in 1835. The causes of the Second at Fort Moultrie, South Carolina. The sev- Seminole War were numerous, but central was the eral hundred Florida Indians under his leadership had refusal of the Seminole to relocate, as prescribed by been waging guerriUa-style warfare against United the 1 830 Indian Removal Act. By the end ofthe war, States forces for a few years. Three months earlier, in 1842, several thousand Seminole had complied with expenses and military casualties mounting, the with the removal. But some hundreds remained in

U.S. Army General Thomas S. Jesup, under the pre- Florida. Their leader, BiUy Bowlegs, was finally de- tense of offering peace negotiations, feated in the Third Seminole War (1855-1858), and had lured Osceola to Saint Augustine, he consented to lead his people to Indian Territory.

~~Florida. When Osceola approached, The ethnic cleansing of Florida was all but complete;~~

Jesup s soldiers had captured and im- as few as 200 Seminole Ungered on, deep in the Ever- prisoned him. The intention had been glades, far removed from American contact. to break the spirit ofhis group ofrene- But who were the Indians known as the Seminole,

~~gades and expedite the removal of all who clung so tenaciously to their homeland? At the the Seminole to lands west ofthe Mis- time ofEuropean contact, in the early 1500s, the tribes~~

sissippi, designated as Indian Territory. in what is now Florida and southeastern Georgia in- The members ofthe other maj or tribes cluded, among others, the Apalachee, Calusa, Guale, inhabiting the southeastern U.S. had Ocale, Potano, Tequesta, Urina, and Yustaga. Those already been forced to make the jour- populations had roots going back thousands of years. ney. They were the Chickasaw, But no tribe named "Seminole" existed. The term Choctaw, Creek, and—^remembered itself did not even come into general use until about Seminole leader Osceola posed for the infamous "Trail ofTears"—the 1760, and it is thought to be a derivative of the Span- proudly even in captivity, as Cherokee. But the Seminole ish dmarron, or shown in this lithograph from were not word meaning "wHd" "untamed."

an 1 838 portrait by George about to give up. What was known as The standard account of Seminole origins is that Catlin. Osceola and his follow- the Second Seminole War would last after two centuries of disease, European conflict, and ers had been resisting reloca- another four years. harsh colonial policies, Florida and southeastern tion out of Florida under the The First Seminole War, from Georgia were essentially devoid ofindigenous groups. terms of the 1830 Indian 1817 until 1818, had also been The region was then repopulated during the mid- Removal Act. fought between U.S. forces and 1700s by Creeks fi-om central Georgia and Alabama. Seminole bands, even though at the time Florida Those Creeks that settled in Florida then became cul-

still belonged to Spain. Among the U.S. justifica- turally distinct and began to be called Seminole. Ac- tions for the incursion was the unwillingness of the Seminole to return fugitive slaves to settlers' plan- Seminole Tommie Jumper wears garb typical for tribesmen living in Florida in the late nineteenth and early twentieth tations. By the time the war ended, many Indian centuries, including turban, scarves, and flowing shirt. Jumper towns in Florida had been burned by General An- was a descendant of Indians who eluded relocation to what is drewJackson, the fliture president, whose scorched- now Oklahoma. The author has investigated the biological earth campaign against the Indians also led Spain to origins of the Seminole, a tribe that did not exist in name at abandon their troubled colony. the time of European contact.

38 NATURAL HISTORY July/August 2005 July/August 2005 NATURAL HISTORY 39 cordingly, Florida's native populations are typically dition to more durable artifacts such as bone, antler, divided into two groups, pre-Seminoie and Semi- and stone tools—textiles, human brain tissue, and nole, in recognition of their disjunctive histories. botanical remains from stomach contents, repre-

That, at any rate, is what the evidence from liis- senting medicinal concoctions and "last meals." torical documents and archaeology shows. But an- Archaeologists distinguish several cultural areas that, other line of evidence can be brought to bear on the by about 2,000 years ago, were the precursors of the

question of Seminole origins: bioarchaeology, the groups encountered by the first European explorers study of human remains excavated from cemeteries in Florida and Georgia. Most groups practiced some and other archaeological sites. Ample physical re- form of horticulture, tending early New World do- mains exist for the crucial time period covering the mesticates such as squash, sunflower, and maize.

transition from the last of the original indigenous Where available, fish and shellfish, as well as terrestri- tribes to the advent of the Seminole. In my research al animals, were an important part of the diet.

~~I have sought to reconstruct genetic relationships and The first European credited with setting foot in~~

~~how they changed among the principal groups, and the Florida peninsula is Juan Ponce de Leon, who~~

I have sought to relate my observations to events explored the coast in 1513. He claimed the penin- known on independent historical or archaeological sula—and much of the surrounding territory as well—for Spain, naming it La Florida, because he discovered it in the Easter season (also known as pasmajlorida, or the feast of the flowers). Other explorers followed, including Panfilo de Narvaez and

Hernando de Soto, but it wasn't until the 1560s, when the French began to position forts along the southeastern coast ofNorth America, that Spain es- tabHshed a permanent colony. In 1565 the Spanish naval officer Pedro Menendez de Aviles expelled the French and founded the city of Saint Augustine. As part ofhis royal charter, Menendez was charged with converting La Florida's indigenous populations to CathoHcism. This task was taken over in 1573 by the Franciscans. During the next 125 years, the fri- ars expanded their reach, converting numerous populations living along the coast ofwhat are now Geor- gia and northern Florida, throughout north-central

Map depicting the Spanisli claim over what is now the south- Florida and adjacent southern Georgia, and in the eastern United States was made in 1742 by the Spanish army Florida panhandle. At the height of missionary ex- royal engineer Antonio de Arredondo. The image, a detail of pansion, during the 1600s, dozens ofmissions served a 1914 copy of the map, shows that some areas were in dis- tens of thousands of converts. pute, but that Spain recognized other areas as legitimately The Spaniards placed their missions in three main occupied by England and France under a 1670 treaty. regions serving three major groups of Native Amer- grounds. The results bring into doubt the "common icans: the Timucua, the Guale (pronounced imlfy),

knowledge" that native Floridians fall neatly into and the Apalachee [see map on opposite page]. The Ti- pre-Seminole and Seminole groups. mucua lived along the northern Atlantic coast of the Florida peninsula, throughout the north-central in- The first people to reach what is now Florida, terior, and in what is now southeastern Georgia. Al- between 12,000 and 10,000 years ago, were no- though they were somewhat unified linguistically, madic hunters and gatherers whose ancestors mi- speaking a dozen or so dialects of one language fam-

grated from Asia into the Americas several thousand ily, they were poHtically divided into as many as fifty years earlier. Some of the earliest known archae- distinct chiefdoms. The Guale, who lived along a ological sites in Florida are also among the most un- narrow strip ofthe Georgia coast, and the Apalachee, usual anywhere in the New World, because they are who lived in the panhandle, were both well-defined wet sites where anaerobic conditions have preserved chiefdoms. They were Unguistically distinct from the organic material that normally decomposes. For ex- Timucua and from each other. The Apalachee were ample, at Windover Farms, near the eastern coast, the most setded ofthe three groups, cultivating maize outside of TitusviUe, a burial pond dating from be- and other crops in a weU-defmed territory bound- tween 7,000 and 8,000 years ago has yielded—in ad- ed by the AuciUa and Ochlockonee rivers. Other in-

40 MATUB.AL HISTORY July/August 2005 digenous groups lived outside the zones proselytized by the inissionaries, particularly in the south of the Florida peninsula. The process of cultural extinction initiated by the Spaniards was stepped up beginning around the mid- 1600s, as Enghsh colonies became established to the north ofSpanish territory. Instigated by the Eng- lish but carried out by their indigenous allies (mainly Creeks), raids were conducted, mostly against the Guale, to obtain slaves. Then, early in the 1700s, EngHsh colonial forces assaulted the Spanish mis- Apalachicoln R: sions. By 1706 the missions outside Saint Augustine had been abandoned or burned, and many Indians Gulf of Mexico had been killed or captured as slaves. A minority of Indians remained Spanish loyalists and retreated to La Florida ca. 1600 the protection of Saint Augustine, while others fled to seek French protection in Louisiana, or disap- Apaiachee region peared into the wild frontier that was central Geor- Guale region gia and Appalachia. The diaspora effectively ended Timucua region thousands of years of regional cultural continuity in Yui Tribe name northern Florida and coastal Georgia. - - Modern state borders

From the early 1500s onward, historical sources Spain established a colonial presence principally in what are now northern and central Florida and southeastern Georgia. document, in increasing detail, the effects of There the Spaniards distinguished three regional groupings European contact on the indigenous peoples of La of indigenous peoples: the Apaiachee and the Guale were Florida. Such sources, however, are neither unbi- each well-defined chiefdoms, but the Timucua were divided ased nor sufficient in themselves. Complementing into as many as fifty separate chiefdoms. the historical data are the resources of archaeology and my own specialty, bioarchaeology. surement is nondestructive—two issues that arise in Bones, and details of their shape, including signs designing studies based on prehistoric DNA. of injuries and muscle attachments, can shed light The skeletal collections at my disposal came from on a population's diet, disease experience, and even cemeteries previously excavated by archaeologists as life activities. Teeth offer similar information: cavi- long ago as the 1940s. For some cemeteries only the ties, tartar, and dental malformations indicate some- enamel, or white portion, of the teeth was pre- thing of the general health of individuals in the past. served; the tooth roots, as well as the rest of the My research focused not on health, however, but skeletons, had decayed in the acidic clay soils. Thus, on two other kinds of data; demographics and mi- I focused my sampling, measurements, and analyses croevolutionary change. My hope was to recon- on dentition, whose form, fortunately, is strongly struct patterns ofgenetic relationship and document influenced by genetics. how those patterns changed through time. Because the populations I was examining were

The task of the demographer is to determine the confined to a relatively small region, and the remains size ofpopulations and identify their members by age of only fifteen or so generations were present, it was and sex. For the indigenous populations, I relied on unlikely that any genetic changes I might find would existing estimates, which are based on human remains have had enough time to evolve through natural se- and other evidence from archaeological sites and, for lection. I was not looking, as paleoanthropologists the postcontact period, on historical sources as well. do, for evidence of long-term adaptive trends, such AH the estimates are subject to error, but they do pro- as the evolution of increased brain size. The genet- vide a baseline for comparative purposes. ic variation I would see would reflect patterns ofmi-

Microevolution, by definition, is any change in gration and the process of genetic drift. gene frequencies within populations of a single spe- Migration, as geneticists define it, encompasses not cies. Such changes appear over short periods oftime, only the literal movements of new individuals into whereas macroevolutionary changes, such as the rise or out of a group, but also any changes in mating (or of new species, take longer. My approach to mi- marriage) patterns that redistribute genetic variation croevolutionary research is to measure skeletal re- across the landscape. For example, if neighboring mains, because they are widely available and mea- groups previously married only among themselves.

~~July/August 2005 NATURAL HISTORY 41 I~~

I but then begin to intermarry, the variety of genes in Second, I estimated the overall level of genetic vari- each group will increase, and the variation in genes ability within the region as a whole—combining all wiU become more homogeneous, or evenly spread, three population groups—and compared genetic across the two groups. variabUity froni one period to the next. Genetic drift arises by chance alone; through pure- The demographic data showed that the stresses of ly random processes, the individuals in a group in one the postcontact period were almost overwhelming for

~~generation may not reflect the full range and pro- all three populations, yet the Apalachee appear to have~~

portion of traits in the preceding generation. Drift is weathered them better than the Guale or the Timu- comparable to the kind of sampling error that poll- cua. The Apalachee population dropped by more than sters have to take into account, and the smaller the 70 percent, from a precontact total of30,000 to about

population, the greater the Ukelihood it will show up. 8,000 by the time the Spanish missions were aban- For example, if only one person in a small group had doned in the early 1700s. But by the mid-1600s, the

all the genes for red hair, and he or she perished in Guale had already declined from several thousand to an accident (in no way attributable to having red several hundred, and the Timucua from more than hair—which would be an example of natural selec- 150,000 to less than a thousand. tion), the group would lose the trait of red hair. Ge- The trends in genetic variability evident in my netic drift tends to reduce genetic variability when samples of the Guale differed sharply from those of populations are declining the Apalachee, and part- and migration bet'ween ly explain the striking

populations is hmited. As contrast in the fate of a consequence, data on the two groups. Among the genetic variability in a length the Guale, variability in- population can provide < > creases as colonization width an independent way ofes- begins, then declines <. > timating changes in pop- rapidly after 1650. In k polar ulation size through time. tooth contrast, among the Apa- lachee, variability does The dental features I not change with ini- measured were the tial colonization, but Tooth length and width, defined as shown in the illustration, as length and width oftooth it increases dramatically well the ratio of length to width, an aspect of tooth shape, are crowns for all four types of after 1650. What caused determined largely by genetics. To study genetic variation and teeth incisors, canines, the difierence? Historical — relatedness among populations of Native Americans, the au- premolars, and molars [see thor examined teeth from archaeologically excavated human sources vaguely note that illustration on this page]. remains. The teeth least subject to nongenetic variation, epidemics ravaged the From these measurements l

influenced by genetics. In all, I examined 1 ,300 indi- Apalachee until much later, perhaps a century later. viduals, enough to have reasonable samples ofpeople living in the Apalachee, Guale, and Timucua regions The sudden, early increase of genetic variability for three discrete time periods: late precontact (A.D. among the Guale reflects immigration, appar- 1300-1400), early mission period (1600-1650), and ently by outsiders showing up in their territory. late mission period (1650—1706). Most likely, Guale groups that had suffered heavy

~~I was primarily interested in two kinds of analy- losses from the epidemics, as well as from conflict~~

sis. First, I explored how genetic variation changed with the Spaniards, were drawing together and be- in each of the three population groups with time. ing joined by other decimated groups. The subse- My reasoning was that if variation was decUning, so quent dechne in variabiUty in the region, the result

~~was the size of the population, because the smaller of genetic drift, is a signal that their numbers then~~

the population the greater the effect of genetic drift steadily fell. In contrast, the Apalachee were still in in reducing variation. Conversely, if variation was an earlier phase of transition by the time the mis- increasing, population was increasing as well, most sions fell and their population was dispersed. likely because previously separate lineages or ethnic The overall level of biological interaction among groups were gathering together for mutual support. the three ethnic groups in precontact times proved

42 NATURAL HISTORY July/August 2005 relatively high. Intergroup warfare, which often re- sulted in the capture ofwomen and children by the victor of a violent encounter, helped ensure genetic mixing. Intergroup marriage and sexual unions imdoubtedly also took place as a result ofother forms of ceremonial and social interaction.

During the early mission period, the Indians in all three regions were converted to Catholicism and united under the banner of Spanish authority. Paradoxi- cally, however, the genetic diiferences among the three regions become more pronounced, not less. By re- stricting small-scale intertribal warfare and, perhaps less intentionally, by interfering with other forms of social interaction, the Spaniards may have reduced the degree of genetic mixing. Ethnic boundaries—and therefore, perhaps, genetic ones—may also have been shored up because the different groups were competing for access to European power and prestige. After 1650, the region-to-region differences shrink dramatically, a sign that mating had expanded across language and ethnic boundaries. The remnant Christian populations had become a single biological population. By 1 750, the indigenous landscape of La Florida had dramatically changed. All the original tribes were gone, and their lands Three factors account for that unification. First, as were being settled by Creeks migrating southward along the local village populations tell to critically low levels, Flint and Chattahoochee rivers. The Creeks in Florida eventually people were forced to bend traditional rules regard- became recognized as a distinct people, the Seminole. Before ing who was a suitable mate. Second, people were those migrations, however, the Creeks themselves had arisen often choosing to migrate over longer distances. Such from a conglomeration of various groups that had sought population shuffling was hastened by Spanish at- refuge in central Georgia and Alabama. The author's data suggest that an important constituent of the Creek population tempts to repopulate strategically important missions. actually descended from some of La Florida's original tribes. Finally, after 1650, England began competing in- tensely with Spain for New World dominance, en- couraging indigenous aUies to carry out slave-raid- an indigenous tribe that had existed for thousands of ing expeditions against the Spanish-aftlhated tribes. years in their region. Even their name was not in-

In that context, I suggest, the tribes in Spanish Flori- digenous: they were referred to by English traders as da minimized their internal ethnic, cultural, and Hn- the Indians living near Ochese Creek (now called the guistic differences. Ocmulgee River); later they were simply called The resident groups in La Florida stUl were iden- "Creeks." During the early to mid-1 700s, some tifiable as Apalachee, Quale, and Timucua. What is Creek groups, principally from central Georgia, most interesting, though, is that from a biological moved down the Flint and Chattahoochee rivers in- perspective, a new, more homogeneous indigenous to Spanish Florida [see map above]. With time, the population was emerging in Spanish Florida. That Florida communities, separated from the Georgia nascent population, never named—and hence in- Creeks by several hundred miles, evolved into the visible to us today—was then widely scattered when Seminole, a distinct tribe that, like the Creeks them- the missions were destroyed. The only Native selves, did not exist in name in precontact times.

American groups that still retain their original iden- My own research does not dispute the arrival of tity today descend from a few Apalachee who, at Creeks from Georgia as the ultimate origin of the that time, fled to the French Louisiana territory. Seminole. But my findings give a new perspective on the biological origin of the Creeks, and by extension, With Florida's tribal areas vacant, the stage was the Seminole. The numbers ofApalachee, Guale, and set for repopularion by Creeks, who Uved in Timucua dropped during the mission period, and the central Georgia and Alabama. Made up of fracmred typical assumption is that disease was at the root ot the populations that had congregated in the Deep South decUnes. But those unhappy with the presence ot the sometime in the 1600s, the Creeks spoke a variety of friai's or Spanish irulitaiy, or imhappy with the in- languages. They constituted a new confederacy, not creasingly um'easonable labor quotas levied by the sec-

~~July/August 2005 NATURAL HISTORY 43 ular government in Saint Augustine, may have sim- land, vacant for only two or three generations.~~

~~ply fled the sphere of Spanish influence. What that If I am right, the genesis of the Seminole as an~~

suggests is that the "Creeks" in the Georgia interior ethnic group does not begin with the movement of may have included ethnic Apalachee, Guale, and an outside population into Florida, but with events Timucua, a nuanced distinction simply ignored or un- that took place a hundred years earher. Gene flow recognized by contemporary European chroniclers. between previously separate groups was the first step

Another clue is the location of the earliest settle- in forging a new identity. It was followed by the dis- ments chosen by the Creeks—or what I would call solution of earher ethnic labels and the shared ex- the proto-Seminole—^who moved into Florida. The perience in the Creek confederacy of Georgia. The impetus for the move has been well documented. In subsequent shared experiences in Florida and in-

part, it was an outcome ofthe Yamasee War of 1715, creasing isolation fi^om the Creek confederacy re- between the Yamasee and the EngUsh in South Car- maining in Georgia promoted the emerging Semi- olina, which worsened relations with the English. nole identity. PoUtical unification, in the 1800s, then At the same time, the Spaniards invited the Creeks came in response to American demands for a Semi- to settle in central and northern Florida, where they nole governing council. The U.S. government's pur- could serve as a bufier between Saint Augustine and pose was to hasten the Seminole's removal to lands west of the Mississippi. After three wars, that goal was nearly accomplished.

~~With the exception of the small community of Apalachee descendants who live today in Louisiana, the ethnic groups inhabiting Florida at the~~

~~time of the first European contact have been con- signed to history, their languages no longer spoken, their customs no longer practiced. The legacy of the~~

Guale is particularly Hmited, perhaps reflecting their early and rapid decline in the wake of the epidemics. Prominently but erroneously—^because the Apalachee Hved along the coastal plain—their tribal name is commemorated in the East's great mountain range, the Appalachians. The Timucua language family hves on in various modern place names, such as the city of Ocala and Tomoka State Park, both in Florida. The images ofthe Timucua themselves—al-

Chief Outina (center) and his warriors, depicted in this scene beit fancifiil in many respects—come down to us in of sixteenth-century Florida by the Flemish artist Theodor de the engravings ofthe sixteenth-century Flemish artist Bry, belonged to one of the original tribes the Europeans en- Theodor de Bry [see illustration on this page]. The encountered in the region. The Spaniards referred to this and " gravings were based on the drawings of Jacques Le other tribes that spoke similar dialects as the "Timucua. Moyne de Morgues, an artist who accompanied the the English colonies. Finally, the rich Florida re- brief French occupation of La Florida. sources made the region inherently attractive. Members of the Creek and Seminole tribal con- A glance at a map of the earliest settlements that federacies who compUed with the provisions of the were destined to be Seminole, however, reveals that Indian Removal Act and endured the hardships of the incoming groups were settling areas formerly Indian Territory are represented by their descendants inhabited by Christian Indians, primarily Apalachee enrolled in the federally recognized Muscogee and Timucua. In my view, then, another major fac- (Creek) and Seminole nations ofOklahoma. The de- tor affected the choice of setthng area: the pohtical scendants ofthe small number ofSeminole who elud- influence of the elite Christian, pro-Spanish Indi- ed capmre in the Florida swamps are now several ans that had left La Florida and interbred with Creek thousand strong. They formed a constitutional gov-

elites. There is even some historical documentation ernment and achieved federal recognition in 1957. that ethnic Apalachee had intermarried with Creek A closely related, but much smaller renegade group, elites in Georgia. Although they were only a mi- the Miccosukee Tribe, has enjoyed separate federal nority of the Creek population, the Apalachee may stams since 1961. Like most up-to-date tribes, they

have been a key component. Their descendants all have Web sites that recount their histories, assert- could have harbored ties to the traditional home- ing, one by one, remarkable stories ot survival. D

~~44 NATURAL HISTORY July/August 2005 ! Help Record a Piece of Natural History~~

Become a Contributor ($25-49), a Supporter ($50-99), a Sponsor ($100-499), a Friend ($500-999), or a Naturalist* ($1,000+). Whatever your level of support, you will be helping to record an important piece of natural history.

~~Send your tax- deductible contribution to:~~

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*Naturalists will he invited to The Explorers Cluh to meet Adam Ravetch and see a film presentation of his work. THIS LAND

~~Sand Trap~~

~~Confined to a mountain valley, windhloum sand has piled up into towering dunes.~~

~~By Robert H. Mohlenbrock~~

More than a hundred miles Rising as high as 750 feet above the long and fifty miles wide, valley floor, they are the centerpiece Bordered by the Sangre de Cristo Mountains the San Luis Valley Hes of the Great Sand Dunes National (background), windblown sand dunes rise within the Rocky Mountains of Park and Preserve. as high as 750 feet above the San Luis south-central Colorado and north- Through volcanic action the San Valley floor. ern New Mexico, bordered on the Juans began to form about 35 million west by the San Juan range and on years ago, and the Sangre de Cristos hard time taking hold. Plants that do the east by the Sangre de Cristo were rapidly upUfted beginning about become established often get buried. range. Dominated by rubber rabbit- 19 million years ago. Rain, vi'ind, Blowout grass and lemon scurf pea brush and grasses, the valley shares and—beginning about 1.6 inilLion are two species that can send out its name with San Luis Creek, a years ago—ice-age glaciers chiseled roots and rhizomes several feet into stream that flows through its north- away at the peaks. Sand, gravel, and the shifting sands, thus ensuring bet- clay were washed into the ter stabilization. South and west of

~~valley, leaving behind lakes the dune field is a flatter, more vege-~~

~~containing sand and silt. tated zone known as the sand sheet,~~

During dry periods, these and today that is the main source of lakes shrank or disap- additional windblown sand. peared, and prevailing southwesterly winds blew Dunes come in various shapes. clouds of sand from the Barchans are crescent-shaped dry lakebeds across the dunes that creep slowly across the

~~valley. Sand grains too landscape as sand is blown over the heavy for the wind to ear- top and slides down the leeward side.~~

ly beyond the crest of the The windward side is the convex side Sangre de Cristos accu- of the crescent. Barchans can also join mulated near the base of end to end to form transverse the mountains. Occasional dunes—rows of sand that run perpen- strong northeasterly winds dicular to the direction of the wind. Prairie sunflowers brighten the sand sheet, also helped trap the sand Parabohc dunes are formed when a relatively flat zone adjacent to the dune field. in the valley and pile it in- the wind causes a blowout, that is, to dunes. begins to gouge sand out from ern half. The more prominent wa- The dunes cover about thirt)' around a patch of vegetation that has

~~terway, however, is the Rio Gi'ande, square miles on the eastern side of the weakened its grip. The excavated~~

which originates in the San Juans valley, in a region near its midpoint. sand is slowly blown forward, but the and flows through the southern part One reason they are so concentrated sand on either side of its path remains

of the valley. The configuration ot here is that several small streams help stabilized by other vegetation. The the two mountain ranges and the capture and return sand blown out of forward-moving pile forms the ceaseless action of wind and \vater this zone. In the dune field, the sand "nose" of a parabola, while the an-

have bestowed upon the valley the is continually shifted back and forth chored vegetation left in place on ei- tallest sand dunes in North America. by the wind, and vegetation has a ther side forms two trailing arms, of-

~~46 NATURAL HISTORY July/August 2005 San Luis Cree/c^Uj, :5iS=, *vs~~

~~yS Great Sand Dunes '^-^ . "^ '^^^ National Park -^gfY*^ and Preserve ^f^ } ^ 1/~~

FOR VISITOR INFORMATION, CONTACT: ten stretching behind tor long dis- Rio Grande National Forest to form Great Sand Dunes National Park tances. Star dunes, with arms that ex- the national preserve. The preserve and Preserve tend from a central point, torm extends up the slopes ot the Sangre 11500 Highway 150 where the winds pummel the sand de Cristos, providing numerous Mosca, Colorado 81 146 from several directions. niches that enhance the biological di- 719-378-6300 www.nps.gov/grsa/ The dunes were first protected in versity in the preserve. Streams and 1932 by the estabhshment of Great small marshy areas within the park Sand Dunes National Monument, provide additional habitats tor plants. found that the dune masses were which embraced fift\'-rune square Although the winds are continu- relatively stable. They did note, rmles. The monument remained es- ally reshaping the dunes, they have however, that nearby marshlands sentially the same size until 2000, not wrought substantial changes in and scattered ponds had become when Congress authorized an expan- living memory. Forest Service sci- dramatically smaller. sion to create the Great Sand Dunes entists E. Durant McArthur and

National Park and Preserve. The first Stewart C. Sanderson compared Robert H. Mohlenbrock is professor major addition was the transfer of photographs of the area taken in emeritus ofplant biology at Southern Illinois about sixt\'-five square miles of the 1936 with conditions in 1990 and University in Carbondale.

Dune In the dune field, mainly where it row-leaf Cottonwood, quaking aspen, and Nevada bulrush, and scratchgrass have a grades into the sand sheet, the most com- thinleaf alder. Skunkbush, trumpet goose- more restricted distribution, westward from mon plants are blowout grass, Indian rice berry, and Woods' rose are shrubs that oc- western Kansas and Nebraska. grass, and lemon scurf pea. Other species cur here and there along the streams. are burr ragweed, crown-leaf evening prim- Among the grasses and herbs are Ken- Mountainside The predominant trees are

~~rose, hairy bugseed, rush skeleton plant, tucky bluegrass, nodding brome, slender Douglas fir, pifion pine, Ponderosa pine.~~

~~and Russian thistle (a nonnative invader). wheatgrass, starry false Solomon's seal, Rocky Mountain juniper, and white fir.~~

The vegetation in the sand sheet is made and western yarrow. Such species as golden currant, mountain up primarily of grasses known as sand mahogany, ocean spray, roundleaf snow- dropseed and sandhill muhly. Among the Marsh Most of the wetland species are com- berry, and wax currant make up the fairly

other species are broom groundsel, James' monly found in marshes in many other parts rich shrub community. A grassy ground catseye, narrow-leaf gromwell, narrow- of the country. Among them are American layer of blue grama, littleseed ricegrass, leaved penstemon, needle and thread, manna grass, bluejoint grass, common mountain muhly, and mutton grass is nodding buckwheat, rubber rabbitbrush, spikerush, common three-square, cowbane, punctuated by wildflowers that include

and yucca. Prairie sunflower brightens the field horsetail, fringed willow-herb, hardstem beardtongue, dainty gilia, Fendler's rag- sand sheet with vivid yellow from late July bulrush, marsh hedge nettle, marsh skullcap, wort, flatspine stickseed, hairy golden through early September. needle spikerush, pinkweed. Rocky Moun- aster, hoary aster, James' buckwheat,

tain iris, swordleaf rush, valley rush, two spe- pygmy flower rock jasmine, sanddune Streambank Large and small creeks are cies of buttercup, and two kinds of arrow- wallflower, tall tumble mustard, and three- lined with such trees as coyote willow, nar- grass. Blue lettuce, Douglas' knotweed. toothed groundsel.

~~July/August 2005 NATURAL HISTORY 47 BOOKSHELF By Laurence A. Marschall~~

live in the British Isles; Asian long- were when they emerged, millions of Out of Eden: horned beetles, which infested New years ago, from the floor of the sea. An Odyssey of Ecological Invasion York City maple trees in Brooklyn in What's more, people are hardly late- by Alan Burdick the mid-1990s, now threaten the trees comers to this process. The Polynesian Farrar, Straus and Giroitx, 2005; ofCentral Park; visitors to Hawai'i who settlers ofHawai'i brought the first pigs $25.00 marvel at the variety of flowers in the to the islands; centuries later, British

tropical island paradise are Hkely to be soldiers carried the first cattle there. Standing in a lush forest on the Pa- admiring plants that are visitors there, Settlers in the New World were dili- cific island of Guam, science writer too; most species of lowland flora in gent both in exporting American in-

Alan Burdick is haunted by an eerie si- Hawai'i were introduced by settlers in digenous plants back across the At- lence. Not a single warble, tweet, or the past few centuries. lantic, and in bringing the plants and chirp can be heard—nothing but the animals of their European home- faint buzz of insects, the passing hum of lands to American soil. Modern air a distant airplane, and the hushed rus- and ocean transportation has only

~~tle of the wind. Guarn's songbirds have accelerated the process.~~

all vanished, victims of the brown tree Burdick began this book, I sense, snake. An exotic predator native to Aus- in an attempt to uncover nature at traUa, New Guinea, and nearby islands its "purest." He found that it was dif-

~~in the eastern Pacific, the snake arrived 1,1 ficult, perhaps impossible, to define unannounced in a military vessel some- ecological purity at all. In most cases,~~

time around 1 949. Such birds as the bri- the leakage ofspecies from one habi- dled white-eye, the Guam flycatcher, tat to another has been going on for and the Mariana fruit dove, once wide- so long that ecologists have no way spread on the island, now exist only as of knowing what an "indigenous" stuffed museum specimens or illustra- ecosystem might look Uke. tions in birders' guidebooks. Even some Moreover, whether an in- nonavian natives—the Mariana fruit vasion is benign or clearly bat, for instance—are rapidly disap- devastating, such as that of pearing under the attack of the re- Guam's brown tree snake, it sourceful reptile. may be impossible to re- Guam may be an extreme case of a verse. One lesson of Bur- habitat devastated by a hungry immi- Box elder infested with Asian dick's odyssey is that there

~~grant. But it is not uniquely vulnerable longhorned beetles (inset) is no such thing as a "state" of na-~~

just because it is a small, isolated island. ture—only a continuous dynamism In 1988 the zebra mussel, once con- Burdick implies that even the that challenges our ability to under- fined to the lakes and rivers ofEurope, "pure" Edenic state is a human in- stand, preserve, and manage. hitched a ride to Lake Erie, presumably vention. Would we know one ifwe saw

in the ballast tanks ofa visiting freighter. it? And if we did, would returning to The Golden Spruce: A True Story Today zebra mussels flourish through- it be environmentally sound? Invasion of Myth, Madness, and Greed out the Great Lakes, and can be found is a process inherent in global ecology. by John Vaillant in the Mississippi River and its tribu- Siberian wooUy mammoths made their WW Norton & Company, 2005; taries, as far south as Orleans. Na- way over the Bering land bridge to the New $24.95 tive clam populations in the Great Lakes New World long before mercantile have been decimated, and other species ships made the journey. Insects and that compete for food with the mussels worms hitchhike the ocean on bits of To the Haida people of the Queen are in sharp decline. Accumulations of flotsam, coming ashore wherever the Charlotte Islands, it was known as zebra mussels clog municipal water sys- winds and currents take them. The ca- K'iid K'iyaas, "the elder spruce." It was

~~tems, and have even been known to pacity ofplant and animal life to spread not the tallest tree in the forest, though~~

sink navigational buoys by their com- over the globe is what made it possible it was stiU a giant by most standards, bined weight alone. for newly emerging landmasses to de- standing 165 feet tall and measuring Burdick points out that nowhere on velop their own indigenous forms of more than twenty feet around at its base. the planet does nature survive in an flora and fauna in the first place. With- At about age 300, it was not the oldest Edenic state, unaffected by nonnative out invasive species, volcanic islands tree in the tribal area, either, for the invasions: American gray squirrels now would have remained as barren as they Queen Charlotte Islands, which lie off

~~48 NATURAL HISTORY July/August 2005 I~~

dent: someone had killed the spruce by protagonist ofJon Krakauer's nonfic- carefully slicing into it with a chain saw tion book Into the Wild, who died in at strategic points around the trunk, the Alaskan wUderness while pursuing cutting nearly all the way through and another personal dream of environ-

~~leaving a hinge of wood just thick mental integrity. VaiUant's book is cut~~

~~enough at its core to keep it upright. from the same cloth. As it moves~~

~~Like the living dead, the tree was poised smartly from scene to scene, with a lit-~~

to crash to the ground with the slight- erary style that betrays its origin as a est breath of wind. New Yorker magazine feature, the author wisely refrains from indulging in The arbocide, it soon emerged, had futile speculation about Hadwin's in- been perpetrated by one Grant ner hfe. Instead, he gives the reader ar- Hadwin, a fortyish logger and surveyor resting descriptions of an exotic land- from the mainland who had become scape, along with illuminating dis- increasingly upset with the environ- courses on plant genetics, the timber mental effects of the big timber indus- business, and the clash between native tries on coastal forests. In a message he culture and corporate capitahsm. His

sent to the local newspapers, Hadwin book is one to ponder and to savor. referred to the spruce as the "pet plant" of the logging companies. Speaking to The Elements of Murder: reporters, he claimed to have no ani- A History of Poison mosity to the native Haida, who ven- by John Emsley erated the tree. Nor, he insisted, was he Oxford University Press, 2005; "Golden Spruce," now gone, was once a insane. Insanity, to Hadwin, was the S3 0.00 beacon of the forest. notion that protecting a few isolated patches of wildness would make up for the central coast of British Columbia, the wholesale rape of old-growth idea of bHss in the dog days of are still home to some of the most an- forests. "When society places so much Mysummer is a comfortable lawn cient stands oftimber on the continent, value on one mutant tree and ignores chair, a cool drink, and a stack of mur- even after nearly a century of logging. what happens to the rest of the forest, der mysteries. For those with similar

~~What was remarkable about the spruce it's not the person who points this out criminal frxations, here's a thick book~~

~~was its color: a lambent yellow, caused who should be labeled." ofnonfiction that might also fiU the bill:~~

~~by a rare genetic mutation that affected But few people saw it that way. To a natural and social history of poisons,~~

~~its ability to make chlorophyll. The un- the Haida, the felling of the spruce by the former Science Writer in Res-~~

usual brightness of its foliage among was comparable to the destruction, idence at the chemistry department of the dense greenery of the Northwest for New Yorkers, of the Twin Towers. the University of Cambridge. John

rainforest made it seem to glow with its Throughout Canada, timber barons and Emsley 's book includes more than any- own inner light, and visitors not famil- environmentahsts alike condemned the one but a fiend would want to know iar with the Haida mythical name al- wanton destruction and called for swift about the uses and abuses of antimony,

ways referred to it as the Golden Spruce. justice. But Hadwin never went to trial. arsenic, lead, mercury, and thallium, For as long as anyone could remem- A few days before his scheduled ap- along with information about a host of ber, the Golden Spruce had stood not pearance, he set out from the mainland elements less commonly ingested but, far from the shore of the Yakoun River, in a kayak, presumably intending to under the proper circumstances, no less which runs through the center of Gra- paddle across the treacherous Hecate deadly: barium, chromium, selenium, ham Island. A local timber company had Strait to his court appearance on Gra- and tellurium among them. set aside a small area of uncut timber ham Island. A few months later the re- The danger of these poisons, well

around the tree, partly as a recreational mains of the kayak and a few of his per- known to pathologists, is that their ef- resource and partly as a gesture to en- sonal possessions were found on an fects can be both cumulative and insid- vironmentalists. But sometime between Alaskan beach, 450 rrules from his point ious. When such toxic elements are en-

January 20 and January 23, 1997, the of departure. Hadwin s disappearance, vironmental, particularly when they oc- Golden Spruce came down, crushing like his strange and desperate act of cur in one's everyday surroundings, one

~~the undergrowth around it and hitting protest, remains cloaked in the mists of can be slowly poisoned without ever be-~~

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~~Joyrides through the X-ray Cosmos reUef, unfortunately, was a mild case of have read The Pale Horse, a classic~~

poisoning. its severe, Christie, Kimberly Weaver mercury At most Agatha whose villain used mercury poisoning causes teeth to fall thaUium salts to knock off his victims. foreword by Riccardo Giacconi out. Because mercury also attacks the ThaUium ions are dead ringers for Reveals how astronomers use color nervous system, even the low doses in potassium ions, one of the metals es- to understand extreme events such as the teething powder no doubt affected sential to health. ThaUium, however, supernovae galactic collisions, the mental development of miUions of does not function quite the same way implosions. eruptions, and steller smiling babies. And smihng adults, too: potassium does. When too much thal- $35.00 hardcover President Lincoln supposedly ingested Uum circulates in the blood, it invades

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tive, which may have led to his reported up the dirt on these and a rogue's gallery ASTRONOMICAL propensity to mood swings. oflesser-known cases. Today, wth ana- ENIGMAS lytical techniques that can routinely sniff That same treacherous subtlety out minute amounts of toxins, villains Life on Mars, the Star of Bethlehem, makes poison the weapon of can no longer count on getting away and Other Milky Way Mysteries choice for many murderers, especially with the perfect murder. But if the

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your palms and the soles of your feet mayhem), in Emsley 's book it's stiU very mer Kidger takes us on a tour of the been thickening lately? Have you been much ahve. solar system, addressing an array of weary, overly irritable, losing appetite fascinating questions . . . Kidger's Laurence A. M.iRSCH.iLL, nuilior of The and weight? Are your eyes red and wa- playful but informed style makes the Supernova Story, is W.K. T. Sahin Professor of tery? Check that elderberry wine your book a joy to read." Physics at Gettysburg College in Pennsylvania, maiden aunts have been serving you, —Publishers Weekly and director of Project CLEA, which produces or those bonbons that keep coming imdcly used siiindatioii software for education in i29.95 hardcover from a secret admirer. You have all the astrouoiiiy. He is the 2005 ii'inner of the Educa- THE JOHNS HOPKINS signs of chronic arsenic poisoning. tion prize of the American Astronomical Society. UNIVERSITY PRESS 1-800-537-5487 • www.press.jhu.edu 52 NATURAL HISTORY July/August 2005 mil ,one at a time, to match nature.net lllRIISIIIIillSIKllllipilS ganized as a time line (www.ngdc.noaa. Chill g ov/pa I eo/ctl/reso urcebeyond.htm I). Out On the home page, scroll down to view a time chart of Earth's ice ages. By Robert Anderson You can click on "About CTL," on the menu at the top of the page, to Summer heat getting you down? learn how best to take advantage of the Then imagine setting your time site's many resources. machine for a geologic era more than half a biUion years ago, when the entire In the 550 million years since the end globe, not just the polar regions, was of the Precambrian era, geologic enveloped in ice. Average surface tem- processes have melted, twisted, reori- peratures reached minus fifty-eight de- ented, deeply buried, or destroyed grees Fahrenheit. Geologists have been much of the oldest rock record. Yet kicking the "snowball Earth" hypoth- through painstaking detective work, esis around for more than a decade, ever geologists have assembled an accurate since the discovery that glacial features map of the continents at the time of the occur in Precambrian rocks over a wide Cambrian explosion. To view a map Elevette^" has more choices in styles, finishes, area of the planet. According to the titled "Late Precambrian Superconti- theory. Earth was exposed to as many nent and Ice House World," return to options and price levels. It also comes with a as four freeze-over episodes, each fol- the "Paleomap Project" (www.scotese. parts warranty no one can beat. Call us today lowed by melting brought on by vol- com/), and from the list at the left of the toearnmoe||^Q||SjAjOR canoes [see "The Longest Winter," by home page, cHck on "Earth History." COMPANY OFJl^AMERICA Gabrielle Walker, April 2003]. Some sci- Once there, click "Precambrian" on the ip DEPT. 3 entists think the catastrophic chmate menu at the left of the page. www.inclinator.com . 800-343-9007 swings may have sparked the so-called Joseph L. Kirschvink, a geologist at RESIDENTIAL ELEVATORS • WHEELCHAIR LIFTS DUMBWAITERS Cambrian explosion, the geologically Caltech specializing in paleomagnet- sudden evolution ofcomplex animal life ics, coined the term "snowball Earth" on Earth. in 1992. At his Web site (www.gps.cal Fossil Murals Try the snowball Earth theory on for tech.edu/users/jkirschvink), you can ac- by Green River Stone Companij size by listening first to a five-minute cess information about past and pre- audio explanation that covers the ba- sent projects ofKirschvink and his lab- sics, at the North Country PubHc Ra- oratory group. One fascinating feature dio online site (go to www.northcountry of his site is an animated reconstruc- publicradio.org/news/natural.php and tion of continental displacements at scroll down to "Natural Selections: about the time of the Cambrian ex- Return to Snowball Earth"). Or go plosion (scroll down the page and click straight to a lengthy but informative on the blue hypertext "iitpw.mov"). text, " 'Snowball' Scenarios ofthe Cryo- The Internet is also the place to go genian," posted in 2002 on an impres- for dissident views. At the Web site of sive Web site called "Palaeos: The Trace NASA's Goddard Institute for Space of Life on Earth" (www.palaeos.com/Pro Studies (www.giss.nasa.gov/research/ terozoic/Snowballs.html). briefs/sohl_01/), you'll find an article by Our private ..fiuinij in Southwest lies at the bottom an To get a good sense of the extreme two geologists at Columbia University. Wyoming of ancient lake. Fifty million years ago, climatic fluctuations conjectured by They simulated climatic conditions fortuitous conditions combined To the theory, visit the site of the "Paleo- during the late Precambrian era, and preserve fish perfectly. map Project" (www.scotese.com/). From found that, even in worst-case scenar- Our technicians remove excess stone the menu at the top left of the page, ios, with reduced solar radiation and using fine hand tools to reveal the click on "Climate History." Scroll low levels of greenhouse gases, the pristine fossils in stunning detail. The down here to the chart titled "Ice oceans would have remained ice free finished fossil mural is a snapshot in House or Hot House." Earth's cHmate near the equator. They dubbed their time, a timeless piece of natural art. history is a fascinating topic, and the model "slushbaE Earth." National Oceanic and Atmospheric

Administration has posted information Robert Anderson is a freelance science about it in a highly accessible form, or- writer Ui'ing in Los Angeles. www.greeariverstoae.com 435-753-4069 July/August 2005 NATURAL HISTORY 53 . e

~~LETTERS (Continuedfrom page 10)~~

feel strongly that including those prim- accurate depictions of a wader. The to the tale [sic]!' These men, with itive Asian taxa in their study would supposed human is articulated more backgrounds in surveying, were not have produced results supporting an Uke an amphibian than a mammal. given to exaggeration, so there is little Asian origin for the group. Early New Mexican artists were reason to doubt their measurements.

As for Deinosuchus, that animal was superb at depicting natural history, so I Lewis and Clark seem also to have undoubtedly one big, mean crocodil- doubt they would represent humans so irdstaken the remains of a prehistoric ian, but to our knowledge, paleontolo- oddly. Why was this image interpreted reptile or dinosaur for those of a fish. gists have yet to recover stomach con- by Ms. Mayor as predation on people? Bruce Meyers tents that include juvenile tyrannosaurs. John M. Marzluff Paulsboro, NewJersey University of Washington Mistaken Identity? Seattle, Washington Adrienne Mayor replies: The Adrienne Mayor's supposition, pre- petroglyph mentioned by John M. sented in her article "Tales From the Adrienne Mayor notes that Native Marzluff is located at Puerco Pueblo in Badlands" [5/05], that fossils may American tribes mistook prehistoric Petrified Forest National Park, which have influenced human legends and dinosaur remains for the remains of the is in Arizona, not New Mexico, as the myths, is certainly reasonable. But I monsters that populated their myths. photo caption incorrecdy states. Some found some of her supporting evi- But they may not have been the only viewers have agreed with Mr. Marzluff dence unconvincing. On page 56, the ones to misidentify the remains. that the carving depicts a frog in the picture of the enormous New Mexi- The Lewis and Clark expedition beak of a wading bird. The long beak can bird snatching up a "human" was recorded an incident on September might support this view, but the large particularly troubUng. I would suggest 10, 1804, that has never been ex- size of the frog seems unrealistic. that the image actually shows a wad- plained. Their journals state that when Other viewers have argued, though, ing bird with a frog. The downward- passing through present-day South that the victim appears to be a strug- curving bill of the bird, the small Dakota, the party "found the back gling human carried by a giant bird. head, and the swollen knees are all bone of a fish, 45 feet long, tapering Teratorns, which are now extinct, were large raptors that co-existed with humans in North America and Greg F. Reinking's snatched up prey with their long beaks. I chose this rock art because I •OSMlCi^ learned that a Hopi elder had associ- "Cosmic Legacy" ated the drawing to old Hopi tradi- tions about giant birds that used to takes you on a journey that begins swoop down and fly off with Hopi with the origin of time, matter and children. His comments are documented in my book. reality, follows the formation of the Bruce Meyers is correct in point- cosmos, life, and humanity, and ing out that Lewis and Clark's mea- presents our interpretations of surements of the immense spine and existence and uhimate destiny. ribs were probably accurate. At the time of the discovery, in 1804, dino-

The motivated reader \\ ill investigate tlie saurs were unknown. The locaHty realities and consequences of cosmolog} and dimensions of the South Dakota quantinn ph>'sics. biological exohition. cogniti^ "fish" have led paleontologists to

~~r science, and human histors from liisloric and modern guess that the creature was a long-~~

\ scientific perspectives with timeless philosopliical insights. necked plesiosaur or a serpentine mosasaur. Fossils of both of these Scientific American. com best seller Mesozoic marine reptiles are abundant in that region. Skeptical Inquirer science best seller Natural History welcomes correspon- dence readers (nhmag@naturalhistory tjikc a quick tour of the Universe from the beginning of creation to present from mag. com). All letters should include a 'inCf'and beyond'' Mcnsa Bulletin daytime telephone number, and all letters

~~- ! ifce at your local bookstore or online at Amazon.com and Barnes & Noble may be editedfor length and clarity. or contact Vantage^^Press at 1-^0-882-3273.~~

~~i :~ ;ii.,~~

~~A dying star is caughtflaring hriejly hack to life.~~

~~By Charles Liu~~

~~When most people see a con- the remarkable objects that make up stellation referred to as these celestial stick figures. Near the~~

~~Sagitta, their first inclina- outstretched arm of Sagittarius, for in-~~

~~tion is to add four letters to make the stance, lies the center ofour Milky Way, word "Sagittarius." Not so fast. The lat- some 25,000 light-years from Earth.~~

ter is indeed the famous archer, one of There, invisible to all but the most spe- the twelve constellations of the zodiac. ciaHzed telescopes, lurks a black hole But Sagitta, the arrow, is an ancient milUons of times the mass of the Sun Nitrogen-filled waterproof its right. Its stars [see "Peering at tlie Edge Time," by Fiil- constellation in own of construction allows use in extreme weather,

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~~Limited lifetime warrant/.~~

~~John R. Thompson, The Center Cannot Hold, 1993~~

~~form a diminutive but distinct flechette, vio Melia, June 2003]. Sagitta harbors sandwiched between AquUa, the eagle, nothing quite so dramatic. Yet one of~~

and Vulpecula, the fox. According to its stars has achieved a kind of minor some versions of sky lore, Sagittarius celebrity as a stellar corpse that has ap- accidentally shot the wayward Sagitta parently risen from the dead. while aiming at nothing in particular. Others say the Greek hero Hercules About a bilHon years before a sun- fired Sagitta at a vulture that was tor- Hke star "dies," or stops generat- menting the captive Titan Prometheus. ing energy via nuclear fusion, it be- Available at Of course, none of our ancestors comes a red giant, growing dramati- who recounted those myths had the cally to a hundred times its original EAGLE OPTICS sUghtest clue about the real identity of (Continued on page 58) 800.289.1132

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~~(Continuedfrom page 55) as tens of millions of degrees. For a lit- Gehrz and his colleagues discovered~~

diameter. Then, as the red-giant phase tle while at least, the core may even that, though the star's overall brightness ends, the star blows ofFits outer layers, flicker back into stellar hfe as a giant and temperature have changed dramat- giving rise to an expanding gas cloud star, generating new energy with new ically through the years, one component called a planetary nebula [see "Ghosts flares of nuclear fusion. ofthe FG Sagittae system has been shin- of Suns Past," by Charles Liu, March Alas, such a "born-again" giant can't ing more or less steadily at a temperature

2004]. The planetary nebula, in turn, last long, because the core is, in es- of about 1,200 degrees F (650 degrees swells in size and drops in density for Celsius). That's roughly hot enough to at most another 100,000 years, expos- A "born-again " giant melt aluminum, but substantially cooling the remaining stellar core at its er than the core of any star undergoing center. That core becomes a white can't last long. active nuclear fiasion. Gehrz and his col- dwarf—the most common celestial ca- leagues conclude that, besides giving daver visible in the sky. The white sence, running on fumes. Without a rise to clouds ofobscuring gas, FG Sagit-

~~dwarf usually radiates its leftover heat substantial fuel source to sustain fusion, tae is powering a strong stellar wind~~

~~into space for billions of years, and it a nuclear re-ignition of this kind runs peppered with carbon dust. They think~~

slowly fades to black. out of gas within a few centuries, and this dust, originating from the star's Some soon-to-be white dwarfs, the star heads back toward white surface, has been glowing continuously

~~however, seem to heed the counsel of dwarfhood. But during its brief return for the past decade. On the basis of the~~

Dylan Thomas; "Do not go gentle in- to fusion-powered Ufe, its interaction measured amount of emitted infirared to that good night." According to the with the surrounding cloud of gas radiation, Gehrz's team estimates that

theory of stellar evolution, the tem- creates a fascinating astronomical lab- the wind is carrying between 1.5 and perature in the stellar core can fluctu- oratory for the study of stellar and in- 7.5 quadrillion (1.5 to 7.5 X lO'^) tons of ate wildly, and sometimes spikes as high terstellar processes. stellar material away firom FG Sagittae The star FG Sagittae, a highly vari- each second—or about eight to forty able star in Sagitta, seems to be a case in Earth masses each year. point. FG Sagittae Hes at the heart of a planetary nebula called He 1-5. In the Sooner rather than later the current past thirty years the star's temperature burst of new nuclear fusion will has dropped firom more than 30,000 de- cease, and FG Sagittae will change grees Fahrenheit to less than 10,000 de- from a born-again giant into a dead-

grees, though its brightness has changed again one. The dusty stellar wind will erratically firom year to year. As with an cease. The stellar core, no longer ob- old, grease-choked diesel engine strug- scured by a thick, dusty blanket, will

~~gUng to start back up, the star's eflibrts turn once more into a hot white dwarf.~~

to restart nuclear fusion create puffs of If, as theoretical models predict, the thick smoke—carbon atoms coughed stellar renaissance of FG Sagittae lasts up from the fading stellar core. The a few hundred years, the wind will

~~smoke absorbs the star's radiating heat deposit thousands of Earth-masses' and periodically obscures the visible worth of carbon-rich matter into the~~

~~light it emits. To see through the haze star's surroundings. The carbon atoms, and examine the goings-on near the as they cool down, could become seeds~~

star's surface, astronomers must look at for the buildup of interstellar dust its radiation in less obscured wave- grains—which, in turn, could seed the lengths, such as infrared light. formation ofasteroids, moons, planets, A research team led by Robert A. and perhaps eventually even life as we

Gehrz of the University of Minnesota know it. Maybe the astronomers of the in MinneapoUs has now done just that. twenty-fourth or twenty-fifth century Recendy the team pubKshed the results will look toward FG Sagittae and see,

of twenty years of monitoring the in- in its surroundings, the potential mak- frared properties of FG Sagittae with ings of a new and distant earth. three telescopes equipped with infrared photometers in effect, photon coun- — Charles Liu is a professor ofastrophysics at the ters. One instrument is in Minnesota, City University of New Yorii and an associate one in Arizona, and one in Wyoming. with die American Museum ofNatural History.

~~58 NATURAL HISTORY July/August 2005 THE SKY IN JULY AND AUGUST By Joe Rao~~

~~Mercury, still near the much brighter August. Onjuly 1 the Red Planet, bril- The planet is not visible again until~~

Venus after their close encounter late liant at magnitude —0.1, is exactly one mid-August, when it appears in the last month, shines in the western astronomical unit—92.9 million east-northeast just before sunrise. A evening twilight at magnitude 0.1 as miles—from Earth. Mars crosses the good time to look for Saturn comes on July begins. Mercury is less than a de- constellation Pisces, the fish, this the morning of August 18, when it gree to the left ofVenus; the two plan- month. On the 1st Mars rises nearly passes five degrees above Mercury.

ets can be found just above the west- due east just before 1 A.M., and it rises northwestern horizon about forty min- about two and a half minutes earlier In July the Moon wanes to new on the utes after sunset. During the following each night thereafter. 6th at 8:02 a.m. It waxes to first quar- two weeks the pair slowly separates, as During August the distance from ter on the 14th at 11:20 A.M. and to Mercury appears to pivot around and Earth to Mars shrinks to 62 million fuU on the 21st at 7:00 A.M. Our satel- below Venus. By the evening of the miles. Mars's brightoess more than dou- lite wanes to last quarter on the 27th

~~13th, Mercury lies three and a half de- bles as a result; it shines Kke a yellow- at 11:19 P.M.~~

~~grees directly below Venus, but Mercury orangejewel, at magnitude —1 ; only one On the night ofJuly 17th a waxing~~

~~appears only about half as bright as it star, Sirius, shines brighter. Mars briefly gibbous Moon occults, or hides, the~~

~~did at the start of the month, so I rec- passes through the constellation Cetus, bright reddish star Antares. The occul-~~

ommend looking through binoculars to the whale, from August 2 through the tation is visible from parts ofthe far west- find the planet. After midmonth Mer- 5th, before moving into the constella- ern and southern United States. Else- cury fades rapidly from the evening sky. tion Aries, the ram, for the rest of the where, Antares seems to pass close to the On August 5 Mercury reaches in- month. At the beginning of August Moon's upper limb. The best views ferior conjunction, passing between Mars rises just before midnight in the come between about 8 P.M. and 9 P.M.

~~Earth and the Sun. Thereafter the plan- east-northeast, and by the 31st it's ris- on the 17th in the Pacific time zone, and~~

~~et rushes up for a good dawn appari- ing before 10:30 P.M. between about 1 A.M. and 2 A.M. on the~~

~~tion during the latter halfofthe month. 1 8th in the Eastern time zone.~~

~~By the 1 7th Mercury has brightened to Jupiter is low in the west-southwest at In August the Moon wanes to new~~

first magnitude and rises seventy-five dusk as July begins, and just gets low- on the 4th at 1 1 :05 RM. It waxes to first minutes before sunup. On the 23rd the er (and sets earher) as the month goes quarter on the 12th at 10:38 P.M. and

~~planet reaches its greatest western elon- on. Jupiter remains in the constellation to full on the 19th at 1:53 RM. It wanes~~

~~gation, eighteen degrees from the Sun. Virgo, the virgin, as it was in June, and to last quarter on the 26th at 1 1 : 1 8 A.M.~~

~~At that point Mercury rises ninety min- the planet is moving eastward toward~~

~~utes before the Sun and has brightened the constellation's brightest star, Spica, The Earth reaches aphelion, its farthest~~

~~further, to magnitude zero. w^ith each passing night; planet and star point from the Sun, on July 5 at 1 :00~~

are separated by about fourteen de- A.M. The Sun is 94,512,036 miles away. Venus has been playing coy for a cou- grees as July commences. ple ofmonths now, but the planet con- In early August Jupiter sets about an The Perseid meteor shower comes every

sents to showing itself ever so slightly hour after dark, and just at the end of August. This year it peaks during the longer in the twilight, as the summer evening twilight as August ends. The predawn hours of the night of August progresses. Although always bright, the planet continues moving eastward 11th. The meteors are fast and bright,

planet remains low in the sky all sum- against the stars toward Spica; the gap and they often leave persistent trails. mer, as seen from midnorthern lati- between them closes to six degrees by From a location free fr-om bright lights tudes. On July 22 binoculars will help the 31st. More notable—and notice- and tall objects, an observer might see show Venus's close pairing with the star able— is the approach of Venus to some fifty to a hundred shooting stars Regulus, the little king, in the con- Jupiter. On the 1st the two planets are an hour. The meteors are called Per- stellation Leo, the lion. The planet and separated by more than thirty degrees, seids because they appear to shoot away star are just a bit more than one degree but by the 31st they are within one and fr-om the constellation Perseus, a hero

~~apart, though the planet is much the a half degree of each other. of Greek myth. Because the Perseids brighter of the pair. usually make their display around Au-~~

~~Venus's apparition in August is AsJuly commences, sky gazers might be gust 10, which the Roman Catholic~~

scarcely changed from what it was in able to see Saturn about forty minutes Church recognizes as the feast of Saint June and July. The planet does make after sunset, just above the west-north- Lawrence, they have been referred to as

~~an approach to Jupiter. western horizon; the planet is about sev- the fiery "tears" of Saint Lawrence. en degrees to the lower right of Mer-~~

~~Mars continues to approach Earth, and cury and Venus. Thereafter Saturn is Unless otheni'ise noted, all times are east-~~

~~so it brightens dramatically in July and swallowed up in the evening twilight. ern daylight time.~~

~~July/August 2005 NATURAL HISTORY 59 .~~

~~At the Museum American Museum S Natural History (J^ www.amnh.org~~

~~Young Naturalist Awards 2005~~

~~A research-based essay contest for students in grades y-12 to promote participation and communication in science~~

Now celebrating its eighth year, Arizona. Over time, huge dry riverbeds been an enemy of my household. It dom- the Young NaturaUst Awards have been carved out of the earth by the inates the ground cover and blocks out

recognizes the accomplishments water. They are dry most of the time, but sunlight. I grew up assuming that I was of students who have investigated ques- during a rainstorm they fdl up with doing a very good deed for the environ- tions in the areas of biology, Earth water. During the rainy season, the ment by depleting the ginger population. science, or astronomy. washes can have up to 15 or 16 feet of I never once wondered, is ginger truly

~~Every year, scientists from the water in them, flowing very swiftly. bad for the environment? Maybe it actu-~~

American Museum of Natural History You might think that this would kill any ally helps native plants." travel far and wide on expeditions to plants in the wash, but grass, bushes, learn more about the natural world. and tiees are able to survive and even Exploring Earthworms' Influences on Following in that tradition, students thrive in this harsh environment." a Miniature Ecosystem, by Remy Robert throughout the United States and (New Orleans, Louisiana; Grade 8) Canada are invited to embark on their The Effects of Hedychium gardnerianum Among the lush variety of plants and own expeditions, but their research can on the Surrounding Soil and Native Flora creatures in her backyard, Remy encoun- be conducted as close to home as their in Volcano, Hawaii, by Mali'o Kodis tered several species ofworms. backyard or a local pond or stream. (Volcano, Hawaii; Grade 7) "The other day, in my backyard, I After identifying a question, students Kahili ginger, an invasive plant, is a slapped a mosquito that had just landed plan how they wiU gather information, threat to the Hawaiian rain forest. Mali'o on my knee and looked out at the spec- conduct outside research to leam more investigates this plant further. trum of paper-thin, satin-soft flowers; the about their topic and possible method- "Ever since I can remember. Kahili bouquets of long, glossy green ginger ologies, observe their subjects, and ginger (Hedychium gardnerianum) has leaves; and the young live oaks. My mind record their findings. Finally, their data analysis leads to conclusions that either answer the original question or lead to further inquiry. Included here are descriptions of and excerpts from the winning essays. Full-length versions of the winning essays and information on how to enter the contest are published on the Mu- seum's Web site at www.amnh.org/ youngnaturalistawards

~~The Pantano Wash: Investigating an Ecosystem, by Daniel Fried (Tucson,~~

Arizona; Grade 7) Intrigued by a local wash, Daniel decided to explore this ecosystem to leam how plants survive during flash floods. "Most people have heard the old say- ing, 'When it rains, it pours.' This is literally true where I live in southern shifted—the wide stretch of grass seemed : Bmtbl<^b(l(Ull^'MI*blI nIgundmBieBMiBiaok PEOPLE AT THE AM NH big to me. How big must it seem to one of the white, microscopic grains-of-sand- Stephanie Fotiadis with-legs crawling around on the fig ivy?" '""aN A/f^ Graphic Designer, National Center for Science Literacy Education Does Effluent Water Affect the l\(/J — Ecosystem and Technology in Fountain Hills, Arizona? by Christina Dnn ty Eilu F tu; Ocwbn l(X low

~~Silvestri (Fountain Hills, Arizona; Grade 8) The town of Fountain Hills, Arizona,~~

uses recycled wastewater to fill a local over-vegetated ecosystem resembling lake. Christina decided to explore the thick green muck. This eutrophication lake's cycles. has greatiy reduced the amount of dis-

~~"On my way to school each day, I pass solved oxygen available to aquatic organ- the Fountain Hills Fountain and park. isms. The rehabilitation of Grovers Mill~~

~~Effluent water is recycled wastewater, Pond and Dam got underway, and I~~

~~used to fill the lake and water the park. wondered what impact the reconstruc-~~

~~At times the lake is fuU of animal and tion might have on Big Bear Brook."~~

~~plant life, at other times the water is~~

~~gloomy, looking as if nothing could The World through a Bat's Ear, by Sarah~~

~~survive. I wondered why the town uses Bayefsky-Anand (New York, New York;~~

effluent water in a public area. I decided Grade 10) to investigate." Sarah's curiosity about bats led her to study how they adjust their echolocation Stephanie Fotiadis Tidal Pools: Bacterial Variability and calls in cluttered environments in order

Marine Life Stability, by Allison Holcombe to orient themselves. (Coto de Caza, California; Grade 9) The work that Stephanie Fotiadis Allison sought to find out how ocean does is seen by millions of kids,

~~temperature and bacterial counts might parents, and teachers every year, but affect tidal pool marine Ufe. Stephanie herself remains behind the~~

~~"Despite their adaptability, tide pools scenes. As the Web Designer for the~~

~~are quite susceptible to the whims of National Center for Science Literacy humankind. Storm drain runoff after a Education and Technology for the past~~

~~significant rain can raise bacterial counts. five and a half years, she has guided the El Nino weather patterns can change look of innovative educational Web~~

~~feeding patterns for much of the native pages. "At the Museum, I really feel like~~

~~marine life. Even the changing of the I am creating something that benefits~~

seasons may cause ambient ocean people, which is rewarding." temperatures to fall. Thus, the formation Stephanie has primary responsibility of my hypothesis for this expedition de- for the creative direction of the Na- pends on the flux of the temperatures of tional Center's Web sites, including the ocean, as well as the resultant change Ology, Resources for Learning, and the

~~in bacterial counts." "During my fieldwork, I had watched Young Naturalist Awards. She is also a~~

~~little brown bats fly adroitiy in the open key member of the production team for~~

~~Impact Study of Grovers Mill Pond and and in cluttered situations, so I pre- each of these projects. "The work we do~~

~~Dam Reconstruction on Big Bear Brook, dicted that these bats would adjust their here is so diverse and interesting. We~~

~~by Eitan Paul (Princeton Junction, New calls according to the setting in which interact with so many people at the Mu-~~

~~Jersey; Grade 9) they operated. I hypothesized that in re- seum and deal with such an array of~~

When plans to reconstruct Grovers sponse to the degree of clutter, these subject matter—every day I learn some- Mill Dam were announced, Eitan won- bats would adjust the features of their thing new."

dered what impact the reconstruction calls, shortening the duration and the Outside the Museum, Stephanie is would have on a local body of water. intervals between calls and increasing an avid tennis fan and a New York City "In the 1800S early settiers in the area the frequency for shorter wavelengths." restaurant connoisseur She has used built a 400-foot-long earthen dam to her skills to produce a tennis Web site trap Big Bear Brook for their grinding The Dance of the Moons, by Elliot as well as to teach an html seminar

~~mOl. Over the years, silt and sediment Alexander (McMinnville, Oregon; in Harlem. have spUled into the pond, creating an Grade 10)~~

The contents of these paces are provided to Natural History by the American Museum of Natural History, Intrigued by Jupiter and its moons, cats live I Our hap- Elliot observed and recorded the posi- o pily in a very tions of the moons so that he could i large, specially construct an accurate model of the equipped pen, but inner Jovian system. I still hate to clean

"I traveled about 50 feet for my field the four smelly lit- trip. But I looked over 300 million ter pans. For years miles. There is one place in the solar I've observed system that puts on a show over a time worms in the span of days or even hours—Jupiter compost piles in and its satellites. First discovered by the woods behind Galileo in 1610, the four innermost our house. Why moons of Jupiter seem to shuttle back not borrow some and forth. At certain times a change is worms from the visible over an hour or less. Since it disposal at an Iowa munitions plant woods and have them clean the cat runs fast, I could measure it in a rela- have led to a contaminated water sup- pans for me.' Having worms clean up tively short period of time." ply and serious health problems for cat mess is my idea of how work people living nearby. Mauree wanted should be done." Troubled Waters: A Six-Month Longitu- to find out what effects the industrial dinal Study of the Spanish Fork River runoff has had on local creeks. A Search for Variable Stars in Two

~~System, by Shannon Babb (Highland, "Over the past three years, I have Northern Open Clusters: NCC 381 Utah; Grade ii) tested water quality using Daphnia and NCC 637, by Morgan MacLeod~~

June suckers are a species offish magna, freshwater invertebrate crus- (Cumberland, Maine; Grade 12) found only in Utah Lake. Concerned taceans that are frequently used in Armed with a ten-inch telescope about their dwindling numbers. water toxicology research because of and a charge-coupled device camera, Shannon decided to investigate the their ability to signal stressful levels of Morgan searched the heavens in water quality of the rivers that feed pollution. Daphnia magna has a light- hopes of finding variable stars in into the lake. sensitive eye, meaning that the eye will open-star clusters.

"For the past three years I have track a moving light source. This "Over the past two years, I investi- been comparing the water quality of knowledge helped me to establish a gated variable stars with amateur tele- measurement of reflex, providing a scopes and charge-coupled device measurement of the effect of environ- cameras. First, the light curves of mental stress on the nervous system." known variable stars were plotted using a charge-coupled device attached to

~~Cot Cats? Cet Worms! by Eric Kimbrough various camera lenses. Then the~~

~~(Prairieville, Louisiana; Grade 12) charge-coupled device was attached to His dislike for cleaning out his cats' the telescope for greater photometric~~

litter boxes led Eric to experiment with accuracy, and a poorly understood vari- worm composting, with amazing results. able star named V377 Cas was observed. "The ultimate purpose of my experi- This research demonstrated that ama-

~~ment is to find an environmentally teur equipment could be extremely ef- friendly solution to animal wastes. fective in collecting photometric data." the rivers flowing into and out of Utah~~

Lake. I have been studying the rivers to figure out which one has the worst water quality. I discovered that the Spanish Fork River was the most pol- luted, [yet] only 12 miles upstream, where the Spanish Fork River flows through Spanish Fork Canyon, the river appears to be healthy."

Environmental Effects of Industrial RunofFon Daphnia magna, by Mauree Gibson (West Point, Iowa; Grade n) Years of improper hazardous-waste Museum Events American Museum 5 Natural History ^ www.amnh.org

~~EXHIBITIONS A lush photographic journey The Grand Tour Fridays and Saturdays, 7:30,~~

LAST CHANCE! from the Andes to the Ama- Tuesday, j/^, 6:^o-'j:}op.m. 8:]0, and g:]op.m. Totems to Turquoise: Native zon to the Chaco. Captions in Dynamic Processes in the Hypnotic visuals and North American Jewelry Arts English and Spanish. Universe rhythms take viewers on a

~~ofthe Northwest and This exhibition is made possible by the Tuesday, 8/2, 6^o-y:]o p.m. ride through fantastical Southwest generosity of the Arthur Ross Foundation. dreanispace.~~

Closes July lo, 200^ This Just In... SonicVision is made possible by generous sponsorship and technology This exhibition celebrates the GLOBAL WEEKENDS July's Hot Topics support from Sun Microsystems, Inc. beauty, power, and symbolism Indigenous Peoples' Day Tuesday, 7/ig, 6:}0-'j:}0 p.m.

~~of the tradition of Native Sunday, 8/'j, i:oo-yoo p.m. August's Hot Topics The Searchfor Life: Are We American arts. An afternoon of films, lec- Tuesday, 8/16, 6:}o-'/:]o p.m. Alone?~~

~~tures, and performances in Made possible through the generous support of Swiss Re. Dinosaurs: Ancient Fossils, recognition of the United Na- Celestial Highlights~~

~~New Discoveries tions' International Day of the The Dog Days of Summer Passport to the Universe~~

~~Through January 8, 2006 World's Indigenous Peoples Tuesday, 7/26, 6:^o-y:]o p.m.~~

The most current thinking on Global Weekends are made possible, The Summer Triangle LARGE-FORMAT FILMS in part, by The Coca-Cola Company, the the mysteries of dinosaurs: Tuesday, 8/]o, 6:]o-y:]o p.m. LeFrak Theater City of New York, and the New York City what they looked like, how Council. Additional support has been For films and showtimes, provided by the May and Samuel Rudin they behaved, and how they PLANETARIUM SHOWS visit www.amnh.org or call Family Foundation, Inc., the Tolan Family moved, as well as why—or and the family of Frederick H. Leonhardt. SonicVision 212-769-5100. even whether—they became extinct LECTURES INFORMATION

Dinosaurs: Ancient Fossils, Neu^ Discoveries Adventures in the Global Call 212-769-5100 or visit www.amnh.org. and its accompanying education and Kitchen: Beer TICKETS AND REGISTRATION public programs are made possible by Bank of America. Tuesday, 7/12, y:oo p.m. Call 212-769-5200, Monday-Friday, 9:00 a.m.-5:oo p.m.,

This exhibition is organized by the With brewmaster or visit www.amnh.org. A service charge may apply. American Museum of Natural History. Garrett Oliver All programs are subject to change. New York (www.amnh.org), in collaboration with the Houston Museum of The Lady and the Panda AMNH eNotes delivers the latest information on Museum Natural Science; California Academy of Thursday, '//14, y:oop.m. events to you monthly via email. Visit Sciences, San Francisco; The Field programs and Museum, Chicago; and North Carolina With author Vicki Croke www.amnh.org to sign up today! Museum of Natural Sciences, Raleigh. The Ape in the Tree Major funding has also been provided Thursday, 7/23, 7:00 p.m. by the Lila Wallace-Reader's Digest Endowment Fund. With paleoanthropologist THE ART OF SC Alan Walker , beautiful measures Exploring Bolivia's Biodiversity Art/Science Collision: The \

Through August 8, 200^ Coney Island Museum Originally conceived by Galileo, this elegant Tuesday, 7/26, '/:00 p.m. thermometer is a With curator Aaron Beebe stunning combination of art and science. "2" Starry Nights * in a glass FAMILY AND Suspended Live cylinder, colorful Jazz CHILDREN'S PROGRAMS spheres rise and fall DR. NEBULA'S LABORATORY with the changing Rose Center for temperature of your Dine Adventure Earth and Space office or home. Saturday, y/2j, 2:oo-y.oo p.m. Available in four sizes. Free shipping. Planetary Vacation Enjoy jazz and tapas on the Call our Personal Saturday, 8/iy 2:oo-y.oo p.m. Shopper at first Friday of every month. 1-800-671-7035. Visit www.amnh.org or call

~~212-769-5100 for lineup. HAYDEN PLANETARIUM PROGRAMS Starry Nights is made possible, TUESDAYS IN THE DOME in part, by Constellation NewEnergy. %j3is:^ Virtual Universe %~~

~~The CONTENTS OF THESE PACES ARE PROVIDED TQ NATURAL HiSTORY 6V THE AMERICAN MuSEUM OF NATURAL HiSTORY. ENDPAPER~~

The natives, however, weren't nearly as thrilled Messing about our activities as we were. By my quick calcula- tion, anywhere between one and two dozen northern green frogs abruptly scattered. A chorus of froggy About "Eeeks!" gave voice to the general havoc. From every direction fi'ogs leaped, skidded, and dived toward the , safety of deeper water. Rocketing from the shoreUne By Dru Clarke at least twelve feet behind me, one skimmed the surface like an artfiolly skipped stone before disappearing underwater. Another perforined a clean, no-splash "Do you know [said Mole], I've never been in a boat be- dive—a 9.8 Olympic qualifier. A third simply jumped fore in all my life. Is it so nice as all that?" straight up and fell, completing a comic cannonball. After a the frogs to the "Nice [said Rat]? It's the only thing. Believe me, my young moment burped surface, friend, there is nothing—absolutely nothing—halfso much a wet circle of improbable profiles. I pondered the worth doing as simply messing about in boats. Simply evolutionary forces that might have led them, de- messing." spite their shared musculature and reflexes, to de- —Kenneth Grahame, Tlie Wind in the Willows velop such a suite of diverse escape maneuvers. Hearing the commotion, the mares and foals in a The pond near our farmhouse swells and re- nearby pasture galloped to the water's edge. They cedes with the seasonal rains, but the last stood dumbly gazing, then lowered their heads to

~~downpour had not swelled it by much. drink, keeping wary eyes on the floating phenome-~~

From where I was standing I could make out a na. The frogs, apparently accustomed to such inter- thick ring of sodden weeds that enclosed a smaller lopers, were unfazed. circle of deep water. But the water was deep enough to float my boat, Anxious for some action, Sukey and I paddled and my custom-made canoe, which weighed in at a over to a pole that was poking out of the water. Atop the pole, perched Hke some cartoon gargoyle,

~~was a huge northern green. As we floated around it~~

~~in circles, the frog remained "on post." Perhaps, in its~~

~~dim ampliibian brain, it thought we couldn't see it. We weren't about to let on that we could.~~

~~It wasn't long before I began to predict the frogs' underwater routes by watching the wakes left by the powerful thrusts of their hind legs. Their predators,~~

too, I mused, must look for similar clues. When a bumper crop of frogs turned up one year in our garden pool, a mob of foraging black-crowned night herons discovered them. Raucous cries from those joyous opportunists tipped us off to the garden party.

They dined on every last fi'og, as if each one were an irresistible, delectable hors d'oeuvre. As the pond shrinks in the summer heat, and the Arthur Rackham, King Log, from Aesop's Fab/es, 1912 frogs become more densely packed around it, a scant thirty-one pounds, was relatively easy to haul similar fate may await these northern greens. A out to the pond and trundle across the gooey muck. more diverse gathering—bobcats, coyotes, foxes, Sukey, my smallest and best dog, hopped into the raccoons—may attend the next garden party. We'll bow and looked around smartly, eager to play the probably miss that one, but we'll be back next double role of ballast and tracker. One push with summer to do some more messing about. the kayak paddle and we slid over the flotsam of

~~reeds and into open water. My other two dogs took Dru Clarke tanght nmi-ine science and ecology in secondary~~

~~oft~ to greet us at the other side of the pond. We school for thirty-one years. She lives in Kansas. Clarke last~~

~~were seriously messing about. wrote for "Endpaper" in September 2003.~~

~~64 NATURAL HISTORY July/August 2005 OPEN NOW~~

~~This groundbreaking multimedia -rich exhibit examines the possibility of environmental~~

~~failure in Southern California by looking~~

~~at ancient civilizations and the lessons~~

~~contemporary societies must lear" ^^ in order to survive. 1 r~~

~~.:»5t»,«ff.^' W^~~

~~.,^;i»^:^iS i| !r,»r^ ji,.~~

~~t^sAVSI~~

~~900 Exposition Boi~~

~~Los Angeles, California 90007 after dark on For more information call FIRST FRIDAYS with dance, music, performance and discussion. 213-763-DINO~~

~~or visit www.nhm.org of Los Angeles County~~

~~The exhibition is made possible by the Annenberg Foundation and supported in part by a generous grant from The Ralph l\J. Parsons Foundation.~~

~~Qy^NENBERG GA)m Promotional support by KCET, Public Television for Southern and Central California, and 89.3 KPCC Southern California Public Radio. OYSTER PERPETUAL GMT-MASTER~~

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~~NEW YORK For an Official Rolex Jeweler call 1-800-3S7-6539. Rolex * Oyster Perpetual and GMT-Master II are trademarks.~~