NEWSFOCUS Was North Africa The Launch Pad on January 7, 2011 For Modern Human Migrations? A growing number of researchers suspect that long-neglected North sophisticated tools and ornaments of famed www.sciencemag.org South African sites such as Blombos Cave Africa was the original home of the modern humans who fi rst trekked (Science, 16 April 2004, p. 369). Few sci- out of the continent entists thought that much of evolutionary signifi cance had gone on in North Africa, LAST YEAR, ARCHAEOLOGISTS EXCAVATING onized the rest of the world come from? “It’s or that the region’s big-toothed, somewhat at the Grotte des Contrebandiers (Smug- a very exciting specimen,” says anthropolo- archaic-looking hominins might be closely gler’s Cave) on Morocco’s Atlantic coast gist Jean-Jacques Hublin of the Max Planck related to the ancestors of many living peo- Downloaded from unearthed a rare prize: the skull and partial Institute for Evolutionary Anthropology in ple. “We’ve left North Africa off the map skeleton of a 7- or 8-year-old child. The fos- Leipzig, Germany. for so long, and now it deserves to be there,” sils, dated to 108,000 years ago, appear to For Hublin, who was born in Algeria, says paleoanthropologist Chris Stringer of belong to an early member of our species, the Contrebandiers child adds to grow- the Natural History Museum in London. although study of them has just begun. ing evidence that North Africa was likely Indeed, a fl urry of research has now put But one feature stands out already: “It a major source of the modern humans who the region fi rmly on the map of human evo- has huge teeth,” says Harold fi rst left humanity’s homeland lution. Thanks to new excavations and more Dibble of the University of and spread into Europe and accurate dating, North Africa now boasts Pennsylvania, co-leader of Asia as early as 130,000 years unequivocal signs of modern human behav- the dig team. That’s a feature ago. “If you look at a map and ior as early as anywhere else in the world, the child shares not only with think how modern humans including South Africa. Climate reconstruc- other hominin fossils found would have moved out, you tions and fossil studies now suggest that across North Africa but also would logically look at North the region was more hospitable during key with some of the fi rst modern Africa,” he says. periods than once thought. The data suggest humans to leave Africa. And Nevertheless, until very that the Sahara Desert was a land of lakes so the new fossil may contain recently, most researchers and rivers about 130,000 years ago, when clues to an enduring mystery studying the origins of Homo moderns fi rst left Africa for sites in what is in human origins research: sapiens looked elsewhere, today Israel. And new studies of hominin Just where in Africa did the Old youngster. This fossil focusing instead on the fos- fossils suggest some strong resemblances— modern humans who fi rst col- child had big teeth. sils of East Africa and the and possible evolutionary connections— CREDITS: HAROLD DIBBLE 20 7 JANUARY 2011 VOL 331 SCIENCE www.sciencemag.org Published by AAAS NEWSFOCUS Digging for our roots. Modern humans Some of these early migrants may have el Ater in eastern Algeria, the tools include occupied many North African sites, like gone east, across the Red Sea and along the triangular objects that some suggested were this one at Contrebandiers, Morocco. southern coast of Arabia. But the earliest used as arrowheads or spear points (see known modern human fossils outside Africa photo, p. 23). At least 100 Aterian sites have between North African specimens suggest a northern route, perhaps through now been uncovered across North Africa, and fossils representing migrations the Nile Valley: Modern human skulls and including in what is now the Sahara Desert. out of Africa between 130,000 and other bones discovered in the early 20th cen- But when archaeologists radiocarbon-dated 40,000 years ago. tury in the Skhul and Qafzeh caves in Israel these sites, they tended to throw out any This barrage of new evidence are now dated to between 100,000 results older than 40,000 years, is reported in recent papers and in and 130,000 years ago, although Online says archaeologist Elena Garcea two new edited volumes (see Addi- researchers debate whether these of the University of Cassino in tional Reading below). Human evo- early colonizers traveled any far- sciencemag.org Italy, because such dates were at Podcast interview lution researchers working in other ther at that early date (Science, with author the limit of the radiocarbon tech- parts of Africa are taking notice. The 9 October 2009, p. 224). Michael Balter. nique and considered unreliable new studies are “long overdue,” says Despite this early connection (Science, 15 September 2006, anthropologist Stanley Ambrose of to the Middle East, not so long ago most p. 1560). “In the past, the Aterian was the University of Illinois, Urbana- experts thought that modern humans occu- thought to be relatively late and not terribly Champaign, who works in East pied North Africa itself relatively late. The exciting, … a sideline or a dead end,” says Africa. They “show that North Afri- earliest known modern human fossils were archaeologist Nick Barton of the University cans may be responsible” for both from East Africa: Skulls and bones found of Oxford in the United Kingdom. early and later H. sapiens migra- near Kenya’s Omo River by Richard Leakey By 1998, however, it began to look like tions out of Africa. Adds archaeolo- and others are now dated to 195,000 years archaeologists might be throwing away the gist Curtis Marean of Arizona State ago, and skulls found at Herto in Ethiopia University, Tempe, “If I were not clock in at about 160,000 years old. Then, working in South Africa, I would in recent years, Hublin, Stringer, and oth- on January 7, 2011 probably be in North Africa.” ers convinced most anthropologists that a But a key question, Marean and 160,000-year-old skull from Jebel Irhoud other researchers say, is whether in Morocco was that of an archaic modern modern humans in North Africa human and not a Neandertal, as previously were foremost among the migrants thought. But that skull was considered an that eventually left Africa, or anomaly, perhaps representing a population whether those populations repre- that got trapped north of the Sahara and then sented an evolutionary cul-de-sac died out. that was left behind when humans from other This picture of North African hominins www.sciencemag.org parts of the continent began moving into as Johnny-come-latelies was reinforced by Asia and Europe. The evidence that North assumptions about the dates of characteris- Africa was a population pool for migrations tic stone tools in the region. Called Aterian to Eurasia is not yet conclusive, says anthro- after their discovery in 1917 at the site of Bir pologist Gerhard Weber of the University of Vienna. Marean is also cautious for now O pioneers. Early modern humans like this one but says the new work should provide “some from Dar es-Soltan (computer reconstruction, Downloaded from good answers in the future.” right) may have spread across North Africa and into Eurasia. Old tools, new dates Given what researchers already know North African hominin sites about modern human evolution, the long neglect of North Africa might seem sur- Pes¸tera cu Oase prising. Most anthropologists think that our species, H. sapiens, fi rst evolved in sub- Mugharet el ‘Aliya Dar es-Soltan Grotte des Pigeons Saharan Africa about 200,000 years El Mnasra Bir el Ater Contrebandiers Grotte du Rhafas Haua Fteah Skhul ago and began migrating out of Jebel Gharbi Africa between 70,000 and Jebel Irhoud Ifri n’Ammar Qafzeh 50,000 years ago, eventually Uan Afuda Nazlet Khater Uan Tabu r colonizing the globe. And ive le R although the expansion has Nil often been considered a single migration, many researchers are beginning to suspect that moderns left Africa in two or more Aterian sites Non-Aterian sites CREDIT: RECONSTRUCTION BY HUBLIN AND NEUBAUER CREDIT: waves. www.sciencemag.org SCIENCE VOL 331 7 JANUARY 2011 21 Published by AAAS NEWSFOCUS wrong dates. That year, researchers used the iers to determine whether is entirely plausible,” says new techniques of optically stimulated lumi- they, too, were used as per- Sarah Tishkoff of the Uni- nescence (OSL) and thermoluminescence sonal ornaments. versity of Pennsylvania. (TL) to date Aterian sites in Libya back to All this implies that the “We can only study popu- 70,000 years, and soon afterward similar Aterian was not a sideshow lations present today, and dates using these and other methods were but a “[cultural] package their present-day distri- found at other Aterian sites in the region. that may be linked with bution probably doesn’t During the past 2 years, the dates have the emergence of mod- reflect where they origi- gotten even older. In 2009, Barton and ern human behavior,” says nated from tens of thou- Abdeljalil Bouzouggar of the National Insti- Barton. That’s not direct sands of years ago.” tute of Archaeological and Heritage Sci- evidence that the Aterians ences in Rabat reported OSL dates of at were the source of out- Rain over the Sahara least 110,000 years from the Aterian site of-Africa migrations, but Facing the past. The Max Planck’s Today, no sensible hom- of Dar es-Soltan in Morocco; and in a new it suggests that they met Jean-Jacques Hublin sees similari- inin would think of trying volume edited by Garcea, the team reports an important prerequi- ties between the Aterians and the to cross the Sahara Desert.