The Catastrophic Extinction of North American Mammoths and Mastodonts

The catastrophic extinction of North American mammoths and mastodonts

Gary Haynes

Abstract

Archaeological and theoretical evidence reviewed here indicates that Clovis-era foragers exterminated mammoths and mastodonts in North America around 11,000 radiocarbon years ago. The process unfolded quickly as human foragers explored and dispersed into fragmenting habitats where megamammal populations were ecologically stressed. Megamammal extinctions were eco-catastrophes with major ripple effects on oral and faunal communities.

Keywords

Mammoth; mastodont; extinction; Palaeoindian; North America; patch choice.

Introduction

Mammoths and mastodonts became extinct in North America soon after 11,000 radiocarbon years before present (RCYBP) (Taylor et al. 1996; Martin and Stuart 1995; Stuart 1991). Thirty-three genera of large mammals (body mass over 44 kg) died out around the same time (Martin and Klein 1984). Distinctive Clovis uted projectile points (Plate 1) also appeared then (see the papers in Bonnichsen and Turnmire 1991). Prehistorians such as C. V. Haynes, Jr. [who is not related to me] have proposed that uted point assemblages represent North America’s earliest archaeological culture because they are the oldest found at virtually every site, locale or subregion where they have been dated. The exceptions are few, such as in Alaska’s Tanana river valley sites (Hamilton and Goebel 1999) or in scattered locales such as Cactus Hill, Virginia (McAvoy and McAvoy 1997) and Meadowcroft Rockshelter, Pennsylvania (Adovasio et al. 1999). But examples of pre- uted-point components are extremely rare (Fiedel 2000). The people who made the Clovis-type uted points are incontestably the rst to arrive in most parts of late Pleisto- cene North America, and therefore are closely linked chronologically with the disappearance of mammoths and mastodonts.

Plate 1 Fluted point (cast) from the Vail site in Maine. Fluted points compared over space and time may differ in morphology and manufacturing techniques.

We know that human hunting can limit or exterminate ungulates with or without climate stress (Alroy 2000; Kay 1994, 1995; Martin 1967, 1982, 1984, 1990; Martin and Steadman 1999; Mithen 1993; Stuart 1999). If the rst settlers in North America targeted large mammals as preferred prey, their opportunistic foraging (Kelly and Todd 1988; Meltzer 1993: 305) may have eradicated mammoth and mastodont populations that had survived earlier cycles of ecological stress during rapid climatic oscillations (Alroy 1999; Martin and Steadman 1999). The removal of mammoths and mastodonts from the New World was an eco- catastrophe that happened swiftly and unexpectedly. Fossils of large mammals show no evidence of climate-caused chronic ill-health or increased vulnerability just before they disappeared (see, for example, Fisher (1996) for information about mastodonts and Duckler and van Valkenburgh (1998) for information about predators). The large mammals – including mammoths and mastodonts – were exterminated so quickly that the geological record provides no direct clues about how it happened. The disappearance of America’s largest forms of animal life would have been a memo- rable event for humans to experience. As well, the disappearance of animals large enough to be true ‘ecosystem engineers’ (see Owen-Smith 1987, 1988, 1999) would have had profound effects on North American ecosystems. Owen-Smith (1987, 1999: 67) has argued that the extinction of megamammals – the animals weighing over 1,000 kg – transformed a minor extinction pulse affected by climate change into a major extinction cascade, because mammoths and mastodonts were ‘keystone’ species that had greatly raised diversity at the patch level. With the megamammals gone, natural processes such as woody regeneration and shrub invasions of grassy glades progressed unimpeded, thus reducing carrying capacity for nonmigratory grazers. Zimov et al. (1995) presented a simulation model showing that the removal of Beringia’s megafauna by human overhunting was as important as climate in shifting the vegetation from highly productive, grass-dominated steppe to poorly productive moss- tundra. Large herbivore feeding has major effects on ecosystems and is known to increase primary productivity in African grassland savanna (Bell 1971), an effect also postulated for California grasslands (Edwards 1992). The process of biome shift due to herbivore Catastrophic extinction of mammoths and mastodonts 393 feeding is now being observed in Yakutia, where large grazers were recently re-introduced into tundra-taiga habitats that may be transformed to steppe in the future (Stone 1998; Zimov et al. 1995: 782–3). lf human foragers did wipe out mammoths and mastodonts in North America and indi- rectly caused the extinctions of other animal species, can we ever discover why and how they managed to do it? My explanation of the process is founded on three propositions: (1) the timing and direction of climate-caused habitat changes were not coupled with extinctions; (2) megamammals were demonstrably killed by human hunters in North America; (3) late Pleistocene foraging in mammoth and mastodont ranges was an optimal strategy for opportunistic hunter-gatherers. These will now be discussed.

Climate-caused changes in habitat were not coupled with extinctions

At the end of the Pleistocene, severe climate reversals occurred out of phase with the extinction event. The Younger Dryas chronozone – a northern hemisphere geological interval of cold that had abruptly reversed warm and wet conditions beginning around 11,000 RCYBP and ending nearly a millennium later (duration and timing are problemati- cal in different world areas (Rutter et al. 2000)) – is sometimes thought to have been the last straw for larger mammals, killing them off completely after they had suffered through several cold to warm reversals following the last Glacial Maximum. Yet the current best-guess chronosequence of events during the glacial to deglacial transition (for example, Fiedel 1999: 106, g. 6) does not support this scenario of extinction based solely on climate. The earliest appearance of foragers who made Clovis uted points was about 11,500 RCYBP (Fig. 1). Some large mammals may have become extinct around 11,200 RCYBP, followed by a near-continental drought beginning 10,900 RCYBP, and the extinctions of all large fauna including mammoths and mastodonts by around 10,800 RCYBP (Graham et al. 1997; Stafford et al. 1997a, 1997b; Holliday 2000; Haynes, C. V. 1991). The Younger Dryas reversal to cold conditions may not have occurred everywhere, and, where it did occur, it followed some extinctions but preceded mammoth and mastodont extinction. In southern South America there may have been no Younger Dryas at all (Bennett et al. 2000; Rodbell 2000), and thus the New World pattern of extinctions is not a direct result of the abrupt onset or end of the Younger Dryas. It is worth noting again that megafauna such as ground sloths, horses, camels, mammoths and mastodonts had universally survived earlier abrupt climate reversals. No clear model can explain how the extinction process tracked changes in climate and habitat at the end of the Pleistocene (see Krech 1999: 38–40 for a précis of the ambigu- ity). But the extinctions do seem to be synchronous with the existence of human foragers who dispersed through the continent within a few centuries of rst appearing.

The Clovis foraging strategy involved killing megamammals

The makers of Clovis-like uted points were present over almost all of North America south of the last glacial ice-fronts, between around 11,500 and 10,500 years ago (Table 1). 14C years B.P. Climate Chronozone or Faunal Event Cultural Event Event 19,500-16,100 Very cold, dry Last Glacial (No extinctions) (Archaeological Maximum remains rare to nonexistent anywhere in continent) 13,000 Warm Bølling (No extinctions) (Archaeological remains rare to nonexistent anywhere in continent) 12,000 Warm Allerød (No extinctions) (Archaeological remains rare to nonexistent anywhere in continent) 11,500 Cold Intra-Allerød (No extinctions) Earliest Clovis cold period radiocarbon dates, very restricted range 11,200 Warm (Unnamed Some large-mammal Clovis present in wide warm interval) extinctions area 10,900 Cold, drier Younger Dryas Clovis becoming locally begins abruptly more variable 10,800 Cold continues All megafauna Clovis-like materials extinctions complete, distributed continent- including mammoths wide and mastodonts 10,200 Warm, wetter Younger Dryas Fluted points no longer ends abruptly made

Figure 1 Correlation of climate changes, hypothesized extinction events and culture in North America. Catastrophic extinction of mammoths and mastodonts 395

A small but inuential literature has argued that Clovis uted point makers were big-game hunters, directly descended (biologically and culturally) from Eurasian Upper Palae- olithic steppe explorers (see, for example, Haynes, C. V. 1987). Scholars who accept this probable connection nevertheless recognize that smaller game and plant resources also would have been eaten (Jennings 1989; Willey 1966). On the other side of the debate are arguments that only plants and small animals were regularly targeted as food, in direct proportion to their existence in Clovis-era habitats (Dent 1995; Dincauze 1993: 285; Meltzer 1993; Meltzer and Smith 1986). The hypothesis that Clovis foragers were mainly plant-food gatherers and smaller-game hunters implies that Pleistocene large mammals were either hunted extremely rarely, especially if populations were dwindling due to climatic stress (Webster and Webster 1984), or were deliberately avoided. The sites where Clovis tools are associated with megamammal skeletons (see below) are therefore considered more likely the evidence of scavenging rather than of killing. However, a comparison of the characteristics that distinguish killing from scavenging (Haynes, G. 1999) indicates some Clovis mammoth associations are cases of actual killing, after all. The basis for comparisons are studies of contemporary bonesites where African elephants were either shot to death or starved during droughts in Zimbabwe

Table 1 Generally accepted radiometric dates on Clovis-point sites (from Holliday 2000; Haynes, C. V. 1993; Taylor et al. 1996). Site Date(s) Material dated

Anzick, MT Average of 3 = 10,820 ± 60 Bone Aubrey, TX Average of 2 = 11,570 ± 70 Charcoal Clovis type site Average of 2 = 11,130 ± 90 Plant remains (Blackwater Draw, NM) Average of 3 = 11,300 ± 240 Plant remains Colby, WY 11,200 ± 220(RL-392) Bone apatite 10,864 ± 141 (SMU-264) Bone collagen Debert, Nova Scotia Average of 13 = 10,590 ± 50 Charcoal Dent, CO Average of 5 = 10,690 ± 50 Bone plus 11,200 ± 500 Domebo, OK Average of 2 = 10,820 ± 230 Carbonized plants Other averages 11,040 ± 250 Bone collagen and gelatin and 10,940 ± 180 Bone collagen and gelatin Lange/Ferguson, SD 11,140 ± 140(AA-905) Charcoal 10,730 ± 530 (I-13104) Bone collagen Lehner, AZ Average of 12 = 10,930 ± 40 Charcoal Murray Springs, AZ Average of 8 = 10,900 ± 50 Charcoal Shawnee-Minisink, PA Average of 2 = 10,640 ± 90 Charcoal Average of 2 more = ~10,900 Charred hawthorne plum seeds Templeton, CT 10,190 ± 300 (W-3931) Charcoal Vail, VT 7 dates, 11,120 ± 180 All but one on charcoal; to 10,040 ± 390 youngest date on humates Whipple, NH Average of 2 = 11,050 ± 300 Charcoal (2 other parts of the site were (Charcoal) dated 9,400 ± 500 to 10,430 ± 300) 396 Gary Haynes

(Haynes, G. 1987, 1988, 1989, 1991). The modern sites are similar in some ways but distinct in other subtle ways (see Haynes, G. 1999; Haynes, G. and Eiselt 1999) (Table 2). If bone representation, weathering stages, carnivore utilization and mortality proles are compared between cultural killsites and noncultural deathsites, the modern sites of elephant bones differ to perceptible degrees when their origins differ. The presence or absence of artifacts is not the dening characteristic that sets apart cultural and noncultural deaths. An examination also has been made of Columbian and woolly mammoth bone assemblages (Haynes, G. 1999). The differences among the sites suggests unambiguously in some cases and ambiguously in others that human behavior created certain sites and natural (noncultural) processes created others, even those with clearly associated artifacts. This evidence does therefore support the idea that Clovis foragers actually killed mammoths individually or in groups.

Empirical and analogical approaches to explaining the role of megamammals in Clovis diets Opinions differ about Clovis subsistence and diet because the methods of reconstructing the possible diet of uted point-makers rely on three distinct lines of evidence: empirical data, ethnographic analogy and theoretical predictions. The three approaches produce different interpretative results.

(a) Empirical evidence Plant and animal remains are scarce at Clovis uted point sites. Yet at least twenty sites contain mammoth or mastodont bones (Table 3) either directly associated with uted points or interpreted as butchered during the Clovis period. The remains of animals other than proboscideans in direct stratigraphic and spatial association with uted points are less abundant (Table 4). Many sites contained no more than teeth or a single element or bone fragment of camel, caribou or other large mammal. Several

Table 2 Comparison of cultural and noncultural elephant bone accumulations. Serial deaths only Variable examined Cultural origin Noncultural origin

Carnivore use Often light Varies Weathering Mixed Mixed Bone representation Selective Nonselective Age prole Varies Selective Mass deaths only Variable examined Cultural origin Noncultural origin

Carnivore use Light to moderate Light to moderate Weathering Mostly similar Mostly similar Bone representation Nonselective Nonselective Age prole Nonselective Selective Catastrophic extinction of mammoths and mastodonts 397

Table 3 Mammoth (Mammuthus columbi) and mastodont (Mammut americanum) sites with Clovis association, or dated to the Clovis time interval. (Note: Fisher (1996) names other late Pleistocene mastodonts he considers butchered by humans in the Great Lakes region, but here I list only two, Heisler and Pleasant Lake in Michigan.)

Site Taxon and number Cultural association/date of animals present

Blackwater Draw, NM Mammoth, 6 Clovis lithics; averaged 3 dates 11,170 ± 110 Burning Tree, OH Mastodont, 1 No lithics, possibly butchered bones; 10,860 ± 70 (Pitt-0832) and 11,390 ± 80 (AA-6980) Colby. WY Mammoth, 7 Clovis lithics; 11,200 ± 220 (RL-392) and 10,864 ± 141 (SMU-254) Dent, CO Mammoth, 13 Clovis lithics; averaged 5 dates 10,690 ± 50, and 11,200 ± 500 Domebo, OK Mammoth, 1 Clovis lithics; averaged 2 dates 10,820 ± 270 Dutton, CO Mammoth, 1 Clovis lithics; <11,710 Escapule, AZ Mammoth, 1 Clovis lithics; no date Heisler, MI Mastodont, 1 No lithics, possibly butchered bones; 11,770 ± 110 (NSRL-282, AA-6979) Hiscock, NY Mastodont, 6 Clovis lithics; 11,390±80 (AA-6977) to 10,515 ± 120 (Beta-24412) Kimmswick, MO Mastodont, 2 Clovis lithics; no date Lange-Ferguson, ND Mammoth, 2 Clovis lithics; 11,140 ± 140 (AA-95) and 10,730 ± 530 (I13104) Lehner, AZ Mammoth, 13 Clovis lithics; averaged 12 dates 10,930 ± 40 Leikum, AZ Mammoth, 2 Clovis lithics; no date Lubbock Lake, TX Mammoth, 2(?) Clovis lithics; >11,100 Miami, TX Mammoth, 5 Clovis lithics; no date Murray Springs, AZ Mammoth, 2 Clovis lithics; averaged 8 dates 10,970 ± 50 Naco, AZ Mammoth, 1 Clovis lithics; no date Navarettej AZ Mammoth, 1 2 Clovis points; no date Pleasant Lake, MI Mastodont, 1 No lithics, possibly butchered bones; 10,395 ± 100 (Beta-1388) Rawlins, WY Mammoth, 1 Untyped lithics; 11,280 ± 350 (I-449) (U.P. mammoth)

Note: Occasionally other megamammal nds with possible Clovis associations have been dated radiometrically well older or younger than Clovis. These examples can be partly explained by the nature of radiocarbon dating – ‘dates’ are only a statistical probability of an object’s age and not a simple ‘fact’ – or by the potential for sites, sediments and samples to be contaminated, or by inappro- priate choices of materials to be dated, or by ‘associations’ that are speculative rather than clearly demonstrated, etc. At least one-half of all radiocarbon dates returned over the past half-century probably have been rejected or suppressed because of suspected errors. This may make readers nervous that the real dates of Clovis and megamammal extinction could be quite different from the 11,500–10,500 radiocarbon years generally accepted. However, when samples are carefully collected and lab protocols followed, the dates much more often come out within the generally expected time interval (see Stafford 1988; Stafford et al. 1987, 1988). studies have been interpreted to indicate that large mammal blood, including that of mammoths, was present on some uted points (Table 5). Hence, the evidence for megammamals in the Clovis diet is ample, but the evidence for food items other than megamammals is scarce. Botanical macrofossils are even more rare 398 Gary Haynes

Table 4 Sites with possible associations of Clovis artefact(s) and animals other than mammoth or mastodont. ‘Clovis lithics’ refers to assemblages containing both Clovis uted points and other stone implements. Not all taxa in the table should be considered food items, and many may be ‘back- ground’ accumulations. Many taxa were represented by only small numbers of bones or teeth. Some sites contained mammoth or mastodont bones, too.

Site Cultural association Taxa

Aubrey, TX Clovis lithics Deer, bison, rabbit, muskrat, shes, birds, turtles, rodents, ground sloth (skin only) Blackwater Draw, NM Clovis lithics Bison, horse, camel, box turtle Bull Brook, MA Clovis lithics Caribou, beaver Colby, WY Clovis lithics Hare, pronghorn, ass, camel, bison Escapule, AZ Clovis points Horse Hiscock, NY Clovis points Caribou, moose/stag-moose, California condor, grebe Holcombe, MI Clovis lithics Caribou Kimmswick, MO Clovis lithics Micromammals (mainly rodents) Lehner, AZ Clovis lithics At least 11 taxa, incl. micromammals, and horse (teeth), camel, bison Murray Springs, AZ Clovis lithics Numerous taxa, incl. micromammals, and horse (teeth), camel, bison Naco, AZ Clovis points Bison Shawnee-Minisink, PA Clovis lithics Fish, micromammals and reptiles Sheriden Cave (or Pit), OH Clovis lithics Turtle, caribou, peccary, giant beaver (Holcombe-like point) Udora, Ontario Nondiagnostic cached Cervid, hare, arctic fox lithics, plus nearby surface Clovis (Gainey?) points Whipple, NH Clovis lithics Caribou

Table 5 The results of blood residue studies on Clovis tools. 1. Gramly (1991, 1993). 2. Hyland et al. (1990); one endscraper out of forty-ve tested had cervid residue. 3. Dixon (1993); Loy and Dixon (1998). 4. Kooyman et al. (2000). 5. Brush and Yerkes (1996); Brush and Smith (1994); Brush et al. (1994). 6. Molyneaux (2000).

Site (reference) Taxa identied

East Wenatchee (Richey-Roberts), WA (Clovis cache) (1) Human, bison, bovine, cervid, rabbit Shoop, PA (l endscraper tested in Clovis site) (2) Cervid Alaskan uted points (3) Mammoth Wally’s Beach, Alberta (Clovis points) (4) Bovid, horse Martins Creek, OH [note: not a proven Clovis site; site contains Elephant, cervid mastodont and deer bones associated with akes and scrapers] (5) Western Iowa (Northern Loess Hills) (6) Cervid Catastrophic extinction of mammoths and mastodonts 399 than small animal remains, and thus very few plant foods are known. Nuts, grains, and perennial roots or tubers require special tools and technologies such as milling stones or rock-lined roasting pits, which are virtually nonexistent in Clovis times (Table 6). Faced with a disappointingly small proportion of sites that indicate anything about diet, some prehistorians bypass the continent-wide empirical evidence and invent site-by-site diets based on what might have been possible. However, judging only on the basis of recovered materials rather than on the basis of possibilities, the logical conclusion is that uted point makers ate megamammals more frequently than anything else known.

(b) Ethnographic analogy Another argument made against megamammal-hunting by Clovis is based on ethnographic literature. There are no known subsistence hunters of megamammals in the world nowadays, except for arctic native whalers. In Africa, elephants are still killed by ivory poachers or people seeking both trade items and food (Fisher 1987, 1992; Duffy 1984); but no longer is meat the main reason for killing elephants in Africa (Sikes 1971: 309–10). Modern subsistence foragers – even those in elephant country – target medium and small game, and rely more on plant foods than on game animals (Lee 1968; see also Meltzer 1988, 1993). Some archaeologists interpreting Clovis subsistence have relied on ethnographic analogues to develop a line of reasoning that Clovis uted point makers, like modern foragers, also never or rarely tried to kill megamammals, and instead chose to forage for a wide range of smaller game, plant foods and aquatic resources (Dincauze 1993; Meltzer 1988, 1993). Tacit in this argument is the idea that foragers procure different food resources in the same proportions the resources occur in local environments. Because there are more smaller animals than megamammals in terrestrial habitats, more small animals would have been hunted. Anthropology’s available ethnographic snapshots are of foragers who no longer live in a world of foragers, and they behave differently from foragers who did live in such a world, where the ability to disperse, explore and exploit resources was less limited (for an example of differences between modern and prehistoric foragers, see Sealy and Pfeiffer 2000). One major difference between Pleistocene and recent foragers has been shown in a study of human bones from two late Pleistocene sites in England: analysis of the bones

Table 6 Clovis sites with milling stones, roasting pits or other tools/facilities suggesting routine use of nuts, seeds or other plant foods. 1. Hester (1972: 107–9). 2. MacDonald (1968: 111, table 15). 3. Spiess and Wilson (1987); Dincauze (1993). Site (reference) Artifact/facility present Comments

Blackwater Draw, NM (1) One grinding stone (‘small mano’) Used for pounding and reciprocal grinding; not known if used for seed preparation or intknapping Debert, Nota Scotia (2) Possible processing implements: Suggested use: processing ‘pulping planes, cleavers’ vegetable products for food or fuel Michaud, ME (3) Possible processing implements: Possibly used for grinding, cobbles pounding, plant processing 400 Gary Haynes shows that the diet at around 12,000 RCYBP consisted mainly of terrestrial animal meat (Richards et al. 2000), unlike the diet of modern foragers which tends to be mostly plant foods (see Lee 1968). Late Pleistocene foraging in North America would have been distinct from the behavior of modern foragers in other ways, as well. During the late Pleistocene, megamammal kills would have been naturally refrigerated or frozen for long periods of time and thus would have ‘kept’ much better than do elephant carcasses in tropical or subtropical Africa and Asia; the preservation would have facilitated a much more efcient use of huge carcasses. Perhaps the convenience of long-term storage encouraged regular hunting of bigger animals. Modern-day ethnographic analogy cannot reliably predict Clovis foraging or subsistence behavior. Clovis foragers colonized an enormous, highly diverse continent with an extremely low human population density, if it had any humans in it at all. Clovis foraging probably differed from tropical foraging in so many ways that analogies should not be trusted when reconstructing Clovis diet. Human nutritional requirements are satised by a great many alternative diets. Speth and Spielmann (1983) demonstrated that high-protein diets (such as from megamammal hunting) require animal fat or carbohydrates to supplement lean meat, otherwise humans would die from protein poisoning or suffer chronic disease. However, even food-stressed mammoths and mastodonts would have provided relatively large packages of fat and meat, some of the fat distributed around the meat, some around viscera and some within bone marrow cavities (Haynes, G. 1991, unpubl. eld notes 1982–7). Megamammal hunters or scavengers would have eaten adequate fat from each megamammal carcass, and avoided protein poisoning. Recent optimal hunter-gatherer diets are modeled as healthy mixtures of plant and animal foods low in fat (Eaton et al. 1997), considered to be an evolutionary ideal. Thus a diet high in megamammal meat and fat may not sound very healthy from the modern perspective, but even a human diet that is ‘high in animal fat and low in vegetable-derived foods is not incompatible with [good] health’ (Johns et al. 2000: 458), according to a recent study of a non-industrialized society. This study suggests that megamammal-hunters would not have been plagued by high cholesterol or other potential problems simply because they ate minor amounts of plant foods with their mammoth meat, if they supple- mented their diet with select roots, gums, resins or barks that provide antioxidants and blood lipid-lowering phytochemicals (Johns et al. 1999, 2000). Finally, as a last rebuttal against using ethnographic analogies to reject Clovis hunting of mammoths, I submit that to argue about the impossibility of megamammal hunting based on the dangers of such a practice is by far the most defective kind of reasoning. A lesson may be learned by reading George Catlin’s eyewitness description of a Plains Indian buffalo surround which turned into ‘a grand turmoil’ and ‘desperate battle’ (Catlin 1989 [1844]: 196, 197) between Minataree hunters and ‘infuriated’ buffalo: unhorsed men ran for their lives in front of pursuing bulls, and hunters leapt from their horses onto the backs of thronging buffalo to escape a crush. These explosive activities were regular occurrences for native American buffalo hunters. Clearly the Minataree hunters Catlin watched were courageous beyond the limits that archaeologists nd in themselves. Like- wise, few if any archaeologists will venture into Arctic waters in a skin boat to go whaling, Catastrophic extinction of mammoths and mastodonts 401 armed with only throwing-boards and harpoons, but arctic native peoples often did so (Yesner 1980), knowing full well the risks. As a native whaler from the Chukotka region of Russia told Makah whaling captain Wayne Johnson, ‘Not everyone’s going to come home all the time [from a whale hunt]’ (Sullivan 2000: 52).

Killing megamammals was optimal foraging at the end of the Pleistocene

The marginal value theorem has been mistakenly interpreted to predict that disappearing species would not have been hunted since they were harder and harder to locate (Webster and Webster 1984; Meltzer and Smith 1986). Based on this reasoning, and taking into account the ethnographic snapshots of foraging behavior mentioned above, an argument has been made that uted point makers did not preferentially hunt mammoths and mastodonts. However, the marginal value theorem (MVT) does not directly predict that foragers reduce their value ranking of a dietary item based exclusively on that item’s scarcity (Charnov 1976; Winterhalder 1981). What the MVT does predict is how foragers evaluate the time spent in a patch looking for food before leaving to seek food in other patches (Fig. 2). Studies of modern foragers show that patch-residence time may increase during periods of climate change, gradual overhunting or forager population growth, because, once foragers become aware that prey abundance is falling, they no longer see good reasons to seek another patch whose prey abundance is also likely to be dropping. Hence, prey depletion may continue in the very patches where hunting pressure is already high (see Smith and Wishnie 2000). Foragers under these and other conditions make subsistence decisions to maximize the harvest of energy per time spent foraging, in spite of possible depletion effects on prey, because protability is the routine goal of foraging – even when it furthers prey depletion (Smith and Wishnie 2000). Mammoths and mastodonts were highly ranked food resources whose presence could be plainly predicted in specic ranges, and whose condition and health could be moni- tored by uted point makers. The presence and the health of megamammals are recorded through observations of the animals and the abundant signs left by them. Like elephants, mammoths and mastodonts would have been great trailmakers and sign-leavers (Plate 2). Modern research on elephants in the wild often relies on studies of dung and other signs to provide data about elephant numbers, diets and health, and the proportions of animals of different ages and sexes (Barnes and Jensen 1987; for examples, see De Boer et al. 2000; Theuerkauf and Ellenberg 2000). Prehistoric foragers would have been skilled trackers and interpreters of the megamammal landscape. Food ranking by foragers reects more than a food item’s abundance – it reects energy return, handling time, reliability, and risk minimization. Certainly Clovis foragers did under- stand how scarce big animals may have been, but this was not the primary consideration when deciding to hunt them. Slow-reproducing resources whose local replacement in patches is perceived as lower than the rate of return from foraging in general will still be harvested, even at unsustainable rates (Clark 1973; Alvard 1998). Although search time may be high, larger animals are rationally ranked highly due to the promise of rich return. For example, a 4,000kg mammoth would have returned about 5,000,000 Kcal of energy (calculated based on 402 Gary Haynes

Figure 2 Marginal value theorem (redrawn from Charnov 1976). The chart shows graphically that a forager who travels a long time to get to a patch will probably decide to stay longer in the patch than a forager who travels a short time. The decision about how long to stay is made based on the patch’s rate of return compared to the average rate of return for all patches. a ratio of 30 per cent body mass salvaged by butchering, and an average value of 4 Kcal per gram of meat [protein]). The next largest mammal of the times, bison, would have returned only a quarter of this amount, but may have been no less dangerous to attack. Instead of spending three days hunting down and processing a bison, optimizing foragers might have chosen to spend twelve days nding and processing one mammoth. Foragers continually evaluate the potential returns from the animals encountered and – as has been demonstrated empirically – reasonably rank the bigger ones highly, if there is a chance of successfully procuring them. Foragers such as those of the late Pleistocene, who were capable of killing megamammals throughout their ranges, would not have avoided killing mammoths or mastodonts when encountered, even though these animals were not always relatively abundant or evenly distributed in their ranges. Pleistocene foragers evaluated their food returns patch-by-patch in the same manner as do foragers in modern times – by reference to average returns from all destination patches (Fig. 2; see Giraldeau 1997). Prior information about resources, prey and the environment is used in making foraging decisions, and the more promising patches are searched for longer times than poorer patches, especially if they are widely separated. If Catastrophic extinction of mammoths and mastodonts 403

Plate 2 An elephant trail in Kalahari sands of Africa. Trails are rich sources of information about animal numbers, health and behavior, plus they make exploratory travel by human foragers easier and less risky.

the richer patches also happened to be the places where megamammals aggregated, these patches would have remained attractive to foragers for relatively long spans of time. A strategy for reducing search time would have been apparent to foragers in the late Pleistocene, if megamammal behavior resembled that of modern megamammals such as elephant and rhinoceros. Foragers of the late Pleistocene, in order to minimize risk, to increase encounter rates, to reduce pursuit time, and to limit their foraging radius, therefore would have actively sought out the very patches where megamammals aggregated. A tremendous advantage that humans have over other animal foragers is that they are omnivorous – they could have comfortably survived in any season by eating a wide variety of other foods while continuing to search for the preferred megamammal prey, even after 404 Gary Haynes mammoths and mastodonts had become scarce due to climate change and overhunting (Owen-Smith, N. 2001 pers. comm.). If uted point makers (1) did hunt megamammals, (2) did not avoid hunting them when extinction began to occur and (3) ate megamammals more than other animal and plant foods, what could be concluded about their continent-wide subsistence preferences? The answer would be that Clovis people preferred to hunt mammoths and mastodonts, and that as foragers their mobility strategies were intended to increase the chances of encoun- tering these megamammals. In other words, in this model Clovis subsistence was an opportunistic specialization in proboscideans. Foraging specialization in a few, preferred resources is a viable strategy when prey diversity is low, and prey tend to aggregate in herds that feed nomadically. In the last deglaciation interval, the largest mammals were distributed non-randomly in different habitats. Not only were megamammals found in clustered aggregations, but they also were re-ordering their range distributions as climatic changes forced oral communities to change their spatial extents and distributions. The main changes in vegetation involved a reduction in mosaic cell sizes (discussed below) or the areal extent of different oral communities contacting each other.

Patch dynamics in the late Pleistocene At the end of the Last Glacial Maximum (LGM) many of the once associated animal species radically (and individually) rearranged their geographic distributions in response to changing climatic factors (Graham and Lundelius 1984; Graham et al. 1996). Some species retreated south, some retreated north and some changed their elevational distributions. Thus ended the existence of Pleistocene ‘mosaics’ of mixed species that do not live together now. In many parts of North America the areas of Pleistocene plant mosaics became more and more separated from each other (King and Saunders 1984), as a result of the post- LGM establishment of broad zones of uniform vegetational types, where biotic diversity was much diminished. The last mosaic areas (woodland abutting steppe near shrubby taxa, for example) had a very reduced distribution at the end of the Pleisto- cene, particularly in localities such as southeastern Arizona, southern Nevada, central Mexico, the Great Lakes region, parts of the Ohio river drainage in Kentucky, and along the limestone-lined floodplains of the Mississippi river in Missouri, all of which are rich fossil-collecting regions that used to be late Pleistocene refugia. The word refugium here is used in the sense of ‘an isolated habitat that retains the environmental conditions that were once widespread’ (Lincoln and Boxshall 1987: 326) and is not the same as ‘refuge’, which refers to space where predators can be avoided (Lincoln and Boxshall 1987: 326). Keystone megamammals in refugia kept biotic diversity relatively high, due to the major impacts of their feeding, trampling and wallowing habits (Laws et al. 1975; Owen- Smith 1987, 1988; Putschkov 1997; Sikes 1971; Western 1991, 1989). Like modern elephants, American mammoth and mastodont populations may have been able to sustain densities of up to two or three individuals per 2km, greater than most other herbivores attain (Owen-Smith 1988, 1999). As Owen-Smith has argued, high densities contributed Catastrophic extinction of mammoths and mastodonts 405 to megamammal ecosystem engineering – such as the pruning of woody plants during feeding, the enlargement of water holes and mineral licks, and the suppression of res by opening up vegetation patches. Hence, once climate changes following the Last Glacial Maximum caused extreme shrinkage of mosaic cells and the wide separation of once-abutting vegetational patches, the diversity and productivity of Pleistocene habitats were dramatically changed. Each different type of cell became isolated, greatly reduced or eliminated. Fewer patches of rich ecotones survived over time. The ranges of grazing and browsing animals were widely separated from each other, except in the refugia which continued to provide a variety of palatable and preferred forage (Fig. 3). Around 11,000 RCYBP, biotic responses to climate change occurred within even shorter spans of time than before, swiftly destabilizing ecosystems (Ammann et al. 2000). Other climatic/palaeoenvironmental trends also served to cluster and isolate the largest

Figure 3 Schematic map showing two diverse mosaic environments separated by zonal vegetation that herbivores nd unpalatable or unpreferred. Terminal Pleistocene refugia may have been mosaics like these. 406 Gary Haynes terrestrial mammals at the end of the Pleistocene. A Clovis-era drought of about 10,900 to 10,650 RCYBP (Haynes, C.V. 1993, 1991) or slightly later (Holliday 1997, 2000) forced mammoths and other large mammals to congregate at a much reduced number of sources of water and forage (see Haynes, C.V. 1984, 1991) in the American West and possibly other regions. Research in the mid-continental Great Lakes region similarly indicates that terminal Pleistocene refugium patches existed there, too, providing either better food, more of the essential dietary minerals or some other requirement in quantities or quality higher than in the surrounding regions (Dreimanis 1967; Fisher 1996). The Hiscock site in northern New York state (Laub 1994; Laub et al. 1988, 1994) contains evidence of lowered water table at the time mastodonts were dying-off there (c. 10,800 RCYBP.). Wells were apparently dug by mastodonts seeking clean water; tusk-tips were broken off during ghts over access to the wells (Laub and Haynes 1998; see Haynes, G. 1991: 126–31). The lowering of water tables resulted either from drought or from changes in Great Lakes hydrology, as the Lakes switched drainage between the St. Lawrence and the Mississippi river systems during deglaciation. At this same time, in the southern part of the continent along the coastal plain adjacent to the continental shelf– such as in Florida – water tables rose as sea levels came up, but the addition of so much water to relatively at land surfaces created stresses similar to the removal of water in other regions, as the plant forage drowned or died from waterlogging. Thus ecological stresses and selective disadvantages existed in mammoth and mastodont populations during the difcult time following the Last Glacial Maximum, and the stresses intensied after 11,000 RCYBP due to rapid climatic reversals, increased seasonality and extremes of seasonal climate patterns, and a severe reduction of preferred habitats. Similar disadvantages can be seen in recent eld studies of large mammals in fragmented and crowded ranges (Owen-Smith 1982, 1988; Rachlow 1997; Rachlow et al. 1998). Large mammals suffer from (1) increased incidence of oftentimes violent agonis- tic encounters; (2) heightened feeding competition leading to mortality of youngest animals rst; and (3) differential reproductive success, as some males successfully breed but others do not, resulting in a reproduction rate much lower than predicted based on numbers of animals alone. Yet, climate change and resultant stresses could not have been the cause of all extinctions. Megafaunal taxa during the Pleistocene partitioned resources and had stereotyped diets. For example, the Florida mastodonts were browsers while mammoths were grazers, a conclusion based on geochemistry, habitat reconstructions and the obvious differences in tooth morphology (Hoppe et al. 1999; Koch et al. 1998). Animals with different stereotyped diets were not uniformly affected by the vegetational changes resulting from the late Pleistocene climate oscillations. Some animals suffered from disappearing forage, but other taxa were favored by changes in plant distributions. For example, Florida’s woodlands did not disappear at the end of the Pleistocene, but its browsing mastodonts did, and it is difcult to explain these out-of-phase phenomena without invoking some agent of mastodont extinction other than habitat change. The late Pleistocene was hard on mammoths and mastodonts, yet no compelling evidence exists from the very end of the Pleistocene that both mammoth and mastodont populations suffered greater stress than they had during earlier climatic oscillations. Megamammals were not just circling the drain before they went down the plughole of Catastrophic extinction of mammoths and mastodonts 407 extinction, although they were less abundant than they had been earlier. How did Clovis foragers respond to the changes in proboscidean vulnerability, distribution, density and behavior? Under the palaeoenvironmental conditions of the end of the Pleistocene, the uted point makers preferentially began to hunt megamammals, seeking them out through patch choices that targeted refugia and high-diversity ecotones. Under the conditions of the end of the Pleistocene, megamammal-aggregation locales would have been preferentially sought for foraging.

Clovis ecology, diet and mammoth-hunting At the level of the entire continent, uted point makers hunted mammoths and mastodonts in the remnant megamammal refugia. As presented here, a model of contin- gent causality explains uted point subsistence, settlement and dispersal in terms of late Pleistocene climatic change, palaeoenvironmental developments, megamammal behav- ioral patterns and rational foraging decisions. The necessary and sufcient causes were serial in occurrence: The rst event A was the climate-driven changing of late Pleistocene habitats, creating isolated refugium patches for megafaunal populations. Early human foragers who hunted medium to large animals such as camels or horses found them easier to locate and kill. Clovis technology – blades, bifaces and uting – developed under changing ecological conditions. Event B was the exploratory dispersal of uted point makers into ranges where mammoths and mastodonts could be found. Resources were predictable in certain patches, and the technology created in response included well-prepared and sturdy tools. Long-distance import of high-quality raw materials raised the cost of the technology, but the practice of lithic caching helped reduce the high costs of tool transport. Megamam- mals were preferred prey; niche width was narrow, since diet breadth was deliberately reduced. Risks were minimized over the long and short terms. The ability to explore and disperse into new ranges was unlimited. Event C was the intensied hunting (and scavenging) of mammoths and mastodonts, along with even wider exploration and dispersal. Overall, the foraging ecology of the rst uted point makers was continentally almost uniform, but the uniformity was overlain by regional and local variability. After megamammals became extinct, a new strategy was devised by human foragers. Resources had become less predictable, and new patches and food resources had to be found through far less exploration. Lighter-weight tools were manufactured in some regions, designed to be functionally exible and generalized. Diet breadths were much wider. This strategy served better in Holocene zonal habitats and the closed woodlands of the eastern continent.

The colonization eco-catastrophe: extinction of megamammals

In summary: (1) Megamammals were ranked very highly for inclusion in the diet of uted point makers. Several factors interacted to encourage high ranking: (a) prey body size was 408 Gary Haynes large, promising hunters huge nutrient returns; (b) migration trails created by megamammals in all likelihood were clear, abundant and rmly established in megamammal ranges, thus prompting human travel and exploration along the same trails that mammoths, mastodonts and many other mammalian species traveled; (c) late Pleistocene climatic changes had comprehensive ill-effects on megamammal behavior and biology, working to the advantage of predatory human groups (cf. also Stuart 1991). (2) Late Pleistocene refugia were actively sought by Clovis people who used mammoth and mastodont trail networks, and were visited either serially or sequentially. By seeking the refugia along established animal trails, uted point makers provided themselves a cost-reducing and risk-minimizing tactic that supported dispersal widely but safely, and lessened the uncertainties of exploring unfamiliar territory so quickly. It is also conceiv- able that human foragers widened their exploratory abilities and improved their foraging success by establishing partnerships with other hunters and scavengers, such as ravens or wolves, as they learned how to locate each other and discovered new clues pointing to hidden game or scattered carcasses (see, for example, Heinrich 1991, 1999). Megamammals were pursued when encountered and were killed or scavenged. The empirical and analogical evidence from major sites supports the interpretation that actual killing of mammoths and mastodonts took place both serially (over short time spans) and en masse (Haynes, G. 1999). Mithen (1993) computer-modeled mammoth predation under a variety of environmental conditions and showed that even relatively low levels of killing by humans would eradicate mammoth populations. The special point I am making here is that hunting pressures by humans were more than merely minimally sufcient to trigger extinctions, and that, in the absence of human hunting, mammoths and mastodonts were capable of recovering from the habitat changes, as they had done during earlier climate-change intervals. (3) Fluted point foraging was not a ‘generalist’ strategy. It was specialized, meaning that niche width was preferentially narrow. However, diet breadth was rationally determined from site to site, and prey switching undoubtedly occurred when necessary. As alterna- tives to megamammals, other foods such as small animals, plants, and aquatic resources were procured after active searching, although less readily than the higher-ranked large mammals. Once mammoths and mastodonts were removed from North American ecosystems, several critical ripple effects would have been seen in ecosystems. First, the New World lost its best trailmakers, whose trail networks had linked optimal resource areas within ecozones and connected the different zones themselves across the entire continent. Many animal taxa would have followed these trails, including migrant foraging humans. The trails linked water sources, fruit and mast patches, mineral licks and optimal feeding tracts where other ungulates also fed. Second, megamammals had pruned woody vegetation around wetlands and stream valleys, thereby incidentally increasing biotic productivity. Megamammals would have trampled back encroaching woody plants around meadows and grassy glades, keeping the open vegetation available for nonmigrating grazing mammals. Proboscideans probably helped create grassy glades where nonmigrating feeders congregated (Guthrie 1984; Owen-Smith 1987, 1999). Of the taxa that became extinct at the end of the Pleistocene, many were nonmigrating grazers and browsers of open country (Owen-Smith 1999). After Catastrophic extinction of mammoths and mastodonts 409 herbivore numbers dropped and the woody plants increased, larger-scale res would have become more frequent, further altering American ecosystems on the patch-scale level and above. Megamammals had many other deep effects on ecosystems. They had deepened and expanded ponded water sources, mineral licks and seepage springs through trampling, digging and wallowing. After extinction, these types of sites would have been much more prone to inlling through colluvial and alluvial processes, thus reducing surface water points. Megamammal dung had nourished millions of insects, but after the extinction of mammoths and mastodonts, some species of dung beetle disappeared (Stock 1972). Mega- mammals had carried large and small seeds in their guts and helped disperse numerous plant taxa by passing the seeds in dung. After extinction, many species of plants changed distribution in response to the loss of such dispersal vectors (Janzen and Martin 1982; also see Barlow 2001; Dudley 1999). And megamammal carcasses and bones had fed numerous taxa of carnivorous predators and scavengers, including large mammalian species such as dire wolf (extinct Canis dirus), avian species such as teratorn (extinct Teratornis merri- ami) and condors (extinct Gymnogyps amplus, extinct Breagyps clarki), and arthropods such as blowy (extinct Protocrysomyia howardae) (Harris and Jefferson 1985; Stock 1972). After megamammal extinction, these species and others began dying out due to a severe reduction in food supply. Ongoing analyses of the extinct Pleistocene taxa (Stafford et al. 1997a, 1997b; Graham et al. 1997) may soon indicate which genera disappeared rst from sampling locales, but more dates are needed on well-preserved bones recovered in controlled contexts, and much more stringent control of the laboratory processing is necessary to ensure that bone chemistry is clearly known and lab pretreatments are comparable (Stafford 1988, 1999, 2000 pers. comm.). If it is ever shown that mammoths and mastodonts survived in North America longer than the other large herbivores and carnivores, then the proposed ripple effects of removing proboscideans will have to be rethought. But currently the radiometric data indicate that all of North America’s largest land mammals became extinct very near 11,000 RCYBP. Human foragers in late Pleistocene North America hunted mammoths and mastodonts, and this hunting led to the dying out for ever of those megamammals.

Acknowledgements

I am grateful to Paul Martin, Norman Owen-Smith and Janis Klimowicz for reading drafts of this paper and suggesting improvements. I alone am responsible for shortcomings. The Zimbabwe Department of National Parks and Wildlife Management has supported my research on megamammal landscapes over the past twenty years, for which I am very thankful. I also thank Adrian Lister for suggesting my name to Peter Rowley-Conwy, editor of this collection of papers about eco-catastrophes.

Anthropology Department (096), University of Nevada, Reno 410 Gary Haynes

References

Adovasio, J. M., Pedler, D., Donahue, J. and Stuckenrath, R. 1999. No vestige of a beginning nor prospect for an end: two decades of debate on Meadowcroft Rockshelter. In Ice Age People of North America: Environments, Origins, and Adaptations (eds R. Bonnichsen and K. L. Turnmire). Corvallis, OR: Oregon State University Press for the Center for the Study of the First Americans, pp. 416–31. Alroy, J. 1999. Putting North America’s end-Pleistocene megafaunal extinction in context: large- scale analyses of spatial patterns, extinction rates, and size distributions. In Extinctions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: Kluwer Academic/Plenum, pp. 105–43. Alroy, J. 2000. An ecologically realistic simulation of North America’s end-Pleistocene megafaunal mass extinction. Journal of Vertebrate Paleontology 20, Supplement 3: Abstracts of Papers, Sixtieth Annual Meeting, Mexico City, 25–8 October, p. 26A. Alvard, M. S. 1998. Evolutionary ecology and resource conservation. Evolutionary Anthropology, 7: 62–74. Ammann, B., Birks, H. J. B., Brooks, S. J., Eicher, U., von Grafenstein, U., Hofmann, W., Lemdahl, G., Schwander, J., Toboslki, K. and Wick, L. 2000. Quantication of biotic responses to rapid climatic changes around the Younger Dryas: a synthesis. Palaeogeography, Palaeoclimatology, Palaeoecology, 159(3–4): 3, 13–47. Barlow, C. 2001. The Ghosts of Evolution: Nonsensical Fruits, Missing Partners, and Other EcoIog- ical Anachronisms. New York: Basic Books. Barnes, R. F. W. and Jensen, K. L. 1987. How to Count Elephants in Forests. African Elephant and Rhino Specialist Group Technical Bulletin Number 1. Bell, R. H. V. 1971. A grazing ecosystem in the Serengeti. Scientic American, 225: 86–93. Bennett, K. D., Haberle, S. G. and Lumley, S. H. 2000. The Last Glacial-Holocene transition in southern Chile. Science, 290: 325–8. Bonnichsen, R. and Turnmire, K. L. (eds) 1991. Clovis: Origins and Adaptations. Corvallis, OR: Oregon State University Press for the Center for the Study of the First Americans. Brush, N. and Smith, F. 1994. The Martins Creek mastodon: a Paleoindian butchery site in Holmes County, Ohio. Current Research in the Pleistocene, 1: 14–15. Brush, N. and Yerkes, R. W. 1996. Microwear analysis of chipped stone tools from the Martins Creek mastodon site, Holmes County, Ohio. Current Research in the Pleistocene, 13: 55–7. Brush, N., Newman, M. and Smith, F. 1994. Immunological analysis of int akes from the Martins Creek mastodon site. Current Research in the Pleistocene, 11: 16–18. Catlin, G. (ed. P. Matthiessen) 1989[1844]. North American Indians (original title Letters and Notes on the Manners, Customs and Conditions of the North American Indians Written During Eight Years’ Travel (1832–1839) Amongst the Wildest Tribes of Indians of North America). New York: Viking Press. Charnov, E. L. 1976. Optimal foraging: the marginal value theorem. Theoretical Population Biology, 9: 129–36. Clark, C. W. 1973. The economics of over-exploitation. Science, 181: 630–4. De Boer, W. F., Ntumi, C. P., Correia, A. U. and Mafuca, J. M. 2000. Diet and distribution of elephant in the Maputo Elephant Reserve, Mozambique. African Journal of Ecology, 38: 188–201. Dent, R. J., Jr. 1995. Chesapeake Prehistory: Old Traditions, New Directions. New York: Plenum. Dincauze, D. F. 1993. Fluted points in the eastern forests. In From Kostenki to Clovis: Upper Pale- olithic – Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York: Plenum, pp. 279–92. Catastrophic extinction of mammoths and mastodonts 411

Dixon, E. J. 1993. Quest for the Origins of the First Americans. Albuquerque, NM: University of New Mexico Press. Dreimanis, A. 1967. Mastodons, their geological age and extinction in Ontario, Canada. Canadian Journal of Earth Sciences, 4: 663–75. Duckler, G. L. and van Valkenburgh, B. 1998. Exploring the health of late Pleistocene mammals: the use of Harris lines. Journal of Vertebrate Paleontology, 18(1): 180–8. Dudley, J. P. 1999. Seed dispersal of Acacia erioloba by African bush elephants in Hwange National Park, Zimbabwe. African Journal of Ecology, 37(4): 375–85. Duffy, K. 1984. Children of the Forest. New York: Dodd, Mead. Eaton, S. B., Eaton, S. B. III and Konner, J. M. 1997. Paleolithic nutrition revisited: a twelve year retrospective on its nature and implications. European Journal of Clinical Nutrition, 51: 207–16. Edwards, S. W. 1992. Observations on the prehistory and ecology of grazing in California. Fremontia, 20(1): 3–11. Fiedel, S. J. 1999. Older than we thought: implications of corrected dates for Paleoindians. American Antiquity, 64: 95–116. Fiedel, S. J. 2000. The peopling of the New World: Present evidence, new theories and future directions. Journal of Archaeological Research, 8(1): 39–103. Fisher, D. C. 1996. Extinction of proboscideans in North America. In The Proboscidea: Evolution and Palaeoecology of Elephants and their Relatives (eds J. Shoshani and P. Tassy). Oxford: Oxford University Press, pp. 296–315. Fisher, J. W., Jr. 1987. Shadows in the forest: ethnoarchaeology among the Efe Pygmies. Doctoral dissertation, Department of Anthropology, University of California, Berkeley. Fisher, J. W., Jr. 1992. Observations of the late Pleistocene bone assemblage from the Lamb Spring site, Colorado. In Ice Age Hunters of the Rockies (eds D. J. Stanford and J. S. Day). Denver and Niwot, CO: Denver Museum of Natural History and University Press of Colorado, pp. 51–82. Giraldeau, L. A. 1997. The ecology of information use. In Behavioural Ecology: An Evolutionary Approach, 4th edn (eds J. R. Krebs and N. B. Davis). Oxford: Blackwell, pp. 42–68. Graham, R. W. and Lundelius, E. L. Jr. 1984. Coevolutionary disequilibrium and Pleistocene extinctions. In Quaternary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp. 223–49. Graham, R. W., Lundelius, E. L., Jr., Graham, M. A., Schroeder, E. K., Toomey, R. S. III, Anderson, E., Barnosky, A. D., Burns, J. A., Churcher, C. S., Grayson, D. K., Guthrie, R. D., Harington, C. R., Jefferson, G. T., Martin, L. D., McDonald, H. G., Morlan, R. E., Semken, H. A. Jr., Webb, S. D., Werdelin, L. and Wilson, M. C. 1996. Spatial response of mammals to late Quaternary environmental uctuations. Science, 272: 1601–6. Graham, R. W., Stafford, T. W. Jr. and Semken, H. A. Jr. 1997. Pleistocene extinctions: chronology, non-analog communities, and environmental change. Paper presented at the American Museum of Natural History, at the Center for Biodiversity and Conservation’s Spring Symposium, 17–18 April, Humans and Other Catastrophes: Explaining Past Extinctions and the Extinction Process, New York City. Gramly, R. M. 1991. Blood residues upon tools from the East Wenatchee Clovis site, Douglas County, Washington. Ohio Archaeologist, 41(4): 4–9. Gramly, R. M. 1993. The Richey Clovis Cache: Earliest Americans aIong the Columbia River. Buffalo, NY: Persimmon Press Monographs in Archaeology. Guthrie, R. D. 1984. Mosaics, allelochemics and nutrients: an ecological theory of late Pleistocene 412 Gary Haynes megafaunal extinctions. In Quaternary Extinctions (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp. 259–98. Hamilton, T. D. and Goebel, T. 1999. Late Pleistocene peopling of Alaska. In Ice Age Peoples of North America: Environments, Origins, and Adaptations of the First Americans (eds R. Bonnichsen and K. L. Turnmire). Corvallis, OR: Oregon State University Press for the Center for the Study of the First Americans, pp. 156–99. Harris, J. M. and Jefferson, G. T. (eds) 1985. Rancho La Brea: Treasures of the Tar Pits. NaturaI History Museum of Los Angeles County Science Series 31. Haynes, C. V., Jr. 1984. Stratigraphy and late Pleistocene extinction in the United States. In Quater- nary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp. 353–65. Haynes, C. V., Jr. 1987. Clovis origin update. The Kiva, 52: 83–93. Haynes, C. V., Jr. 1991. Geoarchaeological and paleohydrological evidence for a Clovis-age drought in North America and its bearing on extinction. Quaternary Research, 35: 438–50. Haynes, C. V., Jr. 1993. Clovis-Folsom geochronology and climatic change. In From Kostenki to Clovis: Upper Paleolithic – Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York: Plenum, pp. 219–36. Haynes, G. 1987. Where elephants die. NaturaI History, 96(6): 28–33. Haynes, G. 1988. Longitudinal studies of African elephant death and bone deposits. Journal of ArchaeologicaI Science, 15: 131–57. Haynes, G. 1989. Late Pleistocene mammoth utilization in northeast Asia and North America. Archaeozoologia, 3(1,2): 81–108. Haynes, G. 1991. Mammoths, Mastodonts, and Elephants: Biology, Behavior, and the Fossil Record. New York: Cambridge University Press. Haynes, G. 1999. The role of mammoths in rapid Clovis dispersal. In Mammoths and the Mammoth Fauna: Studies of an Extinct Ecosystem (eds G. Haynes, J. Klimowicz and J. W. F. Reumer). Deinsia, 6: 9–38. Haynes, G. and Eiselt, B. S. 1999. The power of Pleistocene hunter-gatherers: forward and backward searching for evidence about mammoth extinction. In Extinctions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: Kluwer Academic/Plenum, pp. 71–93. Heinrich, B. 1991. Ravens in Winter. New York: Vintage Books. Heinrich, B. 1999. Mind of the Raven: Investigations and Adventures with Wolf-Birds. New York: Cliff Street Books. Hester, J. J. 1972. Blackwater Locality No. 1: A Stratied, Early Man Site in Eastern New Mexico. Fort Burgwin Research Center (Southern Methodist University) Publication No. 8. Holliday, V. T. 1997. Paleoindian Geoarchaeology of the Southern High Plains. Austin, TX: University of Texas Press. Holliday, V. T. 2000. The evolution of Paleoindian geochronology and typology on the Great Plains. Geoarchaeology, 15(3): 227–90. Hoppe, K. A., Carlson, R. W. and Webb, S. D. 1999. Tracking mammoths and mastodons: recon- struction of migratory behavior using strontium isotope ratios. Geology, 27(5): 439–42. Hyland, D. C., Tersak, J. M., Adovasio, J. M. and Siegel, M. I. 1990. Identication of the species of origin of residual blood on lithic material. American Antiquity, 55(1): 104–12. Janzen, D. H. and Martin, P. S. 1982. Neotropical anachronisms: the fruits the gomphotheres ate. Science, 215: 19–27. Catastrophic extinction of mammoths and mastodonts 413

Jennings, J. D. 1989. Prehistory of North America, 3rd edn. Mountain View, CA: Mayeld Publishing. Johns, T., Mahunnah, R. L. A., Sanaya, P., Chapman, L. and Ticktin, T. 1999. Saponins and phenolic content in plant dietary additives of a traditional subsistence community, the Batemi of Ngoron- goro District, Tanzania. Journal of Ethnopharmacology, 66: 1–10. Johns, T., Nagarajan, M., Parkipuny, M. L. and Jones, P. J. H. 2000. Maasai gummivory: implications for paleolithic diets and contemporary health. Current Anthropology, 41(3): 453–9. Kay, C. E. 1994. Aboriginal overkill: the role of Native Americans in structuring western ecosystems. Human Nature, 5(4): 359–98. Kay, C. E. 1995. Aboriginal overkill and native burning: implications for modern ecosystem management. Western Journal of Applied Forestry, 10(4): 120–6. Kelly, R. C. and Todd, L. C. 1988. Coming into the country: early Paleoindian hunting and mobility. American Antiquity, 53: 231–44. King, J. E. and Saunders, J. J. 1984. Environmental insularity and the extinction of the American mastodont. In Quaternary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp. 315–44. Koch, P. L., Hoppe, K. A. and Webb, S. D. 1998. The isotopic ecology of late Pleistocene mammals in North America – Part 1. Florida. Chemical Geology, 152(1–2): 119–38. Kooyman, B., Tolman, S., Hills, L. V. and McNeil, P. 2000. The archaeological context of late Pleisto- cene remains from the Wally’s Beach site, Alberta. Paper presented at the 65th Annual Meeting of the Society for American Archaeology. Society for American Archaeology Abstracts of the 65th Annual Meeting, 5–9 April Philadelphia, PA. Krech, S., III. 1999. The Ecological Indian: Myth and History. New York: Norton. Laub, R. S. 1994. The Pleistocene/Holocene transition in western New York state: fruits of interdisciplinary studies at the Hiscock site. In Great Lakes ArchaeoIogy and Paleoecology: ExpIoring Interdisciplinary Initiatives for the Nineties (ed. R. I. MacDonald). Waterloo, Ontario: The Quater- nary Sciences Institute, University of Waterloo, pp. 155–67. Laub, R. S. and Haynes, G. 1998. Fluted points, mastodons, and evidence of late-Pleistocene drought at the Hiscock site, western New York state. Current Research in the Pleistocene, 15: 32–4. Laub, R. S., Miller, N. G. and Steadman, D. W. (eds) 1988. Late Pleistocene and Early Holocene Paleoecology and Archeology of the Eastern Great Lakes Region. BuIletin of the Buffalo Society of Natural Sciences 33. Laub, R. S., Dufort, C. A. and Christenson, D. J. 1994. Possible mastodon gastrointestinal and fecal contents from the late Pleistocene of the Hiscock site, western New York state. In Studies in Stratig- raphy and Paleontology in Honor of Donald W. Fisher (ed. E. Landing). New York State Museum Bulletin 481, pp. 135–48. Laws, R. M., Parker, I. S. C. and Johnstone, R. C. B. 1975. Elephants and Their Habitats: The Ecology of Elephants in North Bunyoro, Uganda. Oxford: Clarendon Press. Lee, R. B. 1968. What hunters do for a living, or, how to make out on scarce resources. In Man the Hunter (eds R. B. Lee and I. DeVore). Chicago: Aldine, pp. 30–48. Lincoln, R. J. and Boxshall, G. A. 1987. The Cambridge Illustrated Dictionary of Natural History. Cambridge: Cambridge University Press. Loy, T. H. and Dixon, E. J. 1998. Blood residues on uted points from eastern Beringia. American Antiquity, 63: 21–46. McAvoy, J. M. and McAvoy, L. D. 1997. Archaeological Investigations of Site 44SX202, Cactus Hill, Sussex County, Virginia. Virginia Department of Historic Resources, Research Report Series No. 8. 414 Gary Haynes

MacDonald, G. F. 1968. Debert: A Palaeo-Indian Site in Central Nova Scotia. National Museums of Canada Anthropology Papers No. 16. Martin, P. S. 1967. Prehistoric overkill. In Pleistocene Extinctions: The Search for a Cause (eds P. S. Martin and H. E. Wright). New Haven, CT: Yale University Press, pp. 75–120. Martin, P. S. 1982. The pattern and meaning of Holarctic mammoth extinction. In Paleoecology of Beringia (eds D. M. Hopkins, J. V. Mathews, C. E. Schweger and S. B. Young). New York: Academic Press, pp. 399–408. Martin, P. S. 1984. Prehistoric overkill: the global model. In Quaternary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp. 354–403. Martin, P. S. 1990. 40,000 years of extinctions on the ‘planet of doom’. Palaeogeography, Palaeo- climatology, Palaeoecology, 82: 187–201. Martin, P. S. and Klein, R. G. (eds) 1984. Quaternary Extinctions: A Prehistoric Revolution. Tucson, AZ: University of Arizona Press. Martin, P. S. and Steadman, D. W. 1999. Prehistoric extinctions on islands and continents. In Extinc- tions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: Kluwer Academic/Plenum, pp. 17–55. Martin, P. S. and Stuart, A. J. 1995. Mammoth extinction: two continents and Wrangel Island. Radio- carbon, 37(1): 7–10. Meltzer, D. J. 1988. Late Pleistocene human adaptations in Eastern North America. Journal of World Prehistory, 2: 1–53. Meltzer, D. J. 1993. Is there a Clovis adaptation? In From Kostenki to Clovis: Upper Paleolithic – Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York: Plenum, pp. 293–310. Meltzer, D. J. and Smith B. D. 1986. Paleoindian and Early Archaic subsistence strategies in eastern North America. In Foraging, Collecting and Harvesting: Archaic Period Subsistence and Settlement in the Eastern Woodlands (ed. S. W. Neusius). Center for Archaeological Investigations Occasional Paper 6. Carbondale: Southern Illinois University, pp. 3–31. Mithen, S. 1993. Simulating mammoth hunting and extinction: implications for the late Pleistocene of the central Russian Plain. In Hunting and Animal Exploitation in the Later Palaeolithic and Mesolithic of Eurasia (eds G. L. Peterkin, H. M. Bricker and P. Mellars). Anthropological Papers of the American Anthropological Association, Number 4, pp. 163–78. Molyneaux, B. L. 2000. Update on the Northern Loess Hills Clovis Point. Newsletter of the Iowa Archaeological Society, 50(4): 1–2 Owen-Smith, R. N. 1982. Dispersal and the dynamics of large herbivores in enclosed areas: implications for management. In Management of Large Mammals in African Conservation Areas (ed. R. N. Owen-Smith). Pretoria: HAUM Educational Publishers, pp. 127–40. Owen-Smith, R. N. 1987. Pleistocene extinctions: the pivotal role of megaherbivores. Paleobiology, 13: 351–62. Owen-Smith, R. N. 1988. Megaherbivores: The Inuence of Very Large Body Size on Ecology. Cambridge: Cambridge University Press. Owen-Smith, R. N. 1999. The interaction of humans, megaherbivores, and habitats in the late Pleistocene extinction event. In Extinctions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York, Kluwer Academic/Plenum, pp. 57–69. Putschkov, P. V. 1997. Were the mammoths killed by the warming? Testing the climatic versions of Würm extinctions. Vestnik Zoologii (Journal of the Schmalhausen lnstitute of Zoology, National Academy of Sciences, Ukraine). Catastrophic extinction of mammoths and mastodonts 415

Rachlow, J. L. 1997. Demography, behavior, and conservation of white rhinos. Doctoral dissertation, Program in Evolution, Ecology, and Conservation Biology, University of Nevada, Reno. Rachlow, J. L., Berkeley, E. V. and Berger, J. 1998. Correlates of male mating strategies in white rhinos (Ceratotherium simum). Journal of Mammalogy, 79: 1317–24. Richards, M. P., Hedges, R. E. M., Jacobi, R., Current, A. and Stringer, C. 2000. FOCUS: Gough’s Cave and Sun Hole Cave human stable isotope values indicate a high animal protein diet in the British Upper Palaeolithic. Journal of ArchaeologicaI Science, 27: 1–3. Rodbell, D. T. 2000. The Younger Dryas: cold, cold everywhere? Science, 290: 285–6. Rutter, N. W., Weaver, A. J., Rokosh, D., Fanning, A. F. and Wright, D. G. 2000. Data-model comparison of the Younger Dryas event. Canadian Journal of Earth Sciences, 37: 811–30. Sealy, J. and Pfeiffer, S. 2000. Diet, body size, and landscape use among Holocene people in the southern Cape, South Africa. Current Anthropology, 41(4): 642–55. Sikes, S. K. 1971. The Natural History of the African Elephant. New York: American Elsevier. Smith, E. A. and Wishnie, M. 2000. Conservation and subsistence in small-scale societies. Annual Review of Anthropology, 29: 493–524. Speth, J. D. and Spielmann, K. 1983. Energy source, protein metabolism, and hunter-gatherer subsistence strategies. Journal of Anthropological Archaeology, 2: 1–31. Spiess, A. and Wilson D. B. 1987. Michaud: A Paleoindian Site in the New England-Maritimes Region. Maine Archaeological Society Occasional Publications in Maine Archaeology 6. Stafford, T. W., Jr. 1988. Accelerator 14C dating of late Pleistocene megafauna. Current Research in the Pleistocene, 5: 41–3. Stafford, T. W., Jr. 1999. Chronologies for the oldest human skeletons in the New World. Geological Society of America, 31(7)(Annual Meeting, Abstracts with Program): 24. Stafford, T. W., Jr., Jull, A. J. T., Brendel, K., Duhamel, R. C. and Donahue, D. 1987. Study of bone radiocarbon dating accuracy at the University of Arizona NSF Accelerator Facility for Radio- isotope Analysis. Radiocarbon, 29(1): 24–44. Stafford, T. W., Jr., Brendel, K. and Duhamel, R. C. 1988. Radiocarbon, 13C and 15N analysis of fossil bone: removal of humates with XAD-2 resin. Geochimica et Cosmochimica Acta, 52: 2257–67. Stafford, T. W., Jr., Graham, R. W., Semken, H. A., Jr. and Southon, J. 1997a. AMS 14C chronologies for late Pleistocene mammal extinctions and human migrations in North America. Abstracts of 1997 CAVEPS (on-line: ), University of New South Wales. Stafford, T. W., Jr., Graham, R. W., Semken, H. A., Jr. and Southon, J. 1997b. Chronology and timing of the terminal Pleistocene extinction event in the mid-latitudes of North America. Paper presented at 7th International Theriological Congress, Acapulco, Mexico. Stock, C. 1972. Rancho La Brea: A Record of Pleistocene Life in California, 6th edn. Los Angeles County Museum of Natural History Science Series No. 20, Paleontology, No. 11. Stone, R. 1998. A bold plan to re-create a long-lost Siberian ecosystem. Science, 282: 31–4. Stuart, A. J. 1991. Mammalian extinctions in the late Pleistocene of northern Eurasia and North America. Biological Reviews, 66: 453–562. Stuart, A. J. 1999. Late Pleistocene megafaunal extinctions: a European perspective. In Extinctions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: Kluwer Academic/Plenum, pp. 257–69. Sullivan, R. 2000. A Whale Hunt. New York: Scribner. 416 Gary Haynes

Taylor, R. E., Haynes, C. V., Jr. and Stuiver, M. 1996. Clovis and Folsom age estimates: stratigraphic context and radiocarbon calibration. Antiquity, 70(269): 515–25. Theuerkauf, J. and Ellenberg, H. 2000. Movements and defaecation of forest elephants in the moist semi-deciduous Bossematié Forest Reserve, Ivory Coast. African Journal of Ecology, 38(3): 258–61. Webster, D. and Webster, G. 1984. Optimal hunting and Pleistocene extinction. Human Ecology, 12: 275–89. Western, D. 1989. The ecological value of elephants: a keystone role in African ecosystems. In The Ivory Trade and the Future of the African Elephant, Vol. 2, Section 5.2 (co-ordinator S. Cobb). Oxford: The Ivory Trade Review Group. Western, D. 1991. When the forest falls silent. In Elephants: The Deciding Decade (ed. R. Orenstein). Toronto, Ontario: Key Porter, pp. 83–95. Willey, G. R. 1966. An Introduction to American Archaeology, Vol. 1, North and Middle America. Englewood Cliffs, NJ: Prentice-Hall. Winterhalder, B. 1981. Optimal foraging strategies and hunter-gatherer research in anthropology: theory and models. In Hunter-Gatherer Foraging Strategies: Ethnographic and Archaeological Analyses (eds B. Winterhalder and E. A. Smith). Chicago: University of Chicago Press, pp. 13–35. Yesner, D. R. 1980. Maritime hunter-gatherers: ecology and prehistory. Current Anthropology, 21: 727–50. Zimov, S. A., Chuprynin, V. I., Oreshko, A. P., Chapin, F. S. III, Reynolds, J. F. and Chapin, M. C. 1995. Steppe-tundra transition: a herbivore-driven biome shift at the end of the Pleistocene. American Naturalist, 146: 765–94.