Scavenging_or_hunting_in_early_hominids.pdf

PAT SHIPMAN Johns Hopkins University

Scavenging or Hunting in Early Hominids: Theoretical Framework and Tests

Evidence from Bed I , Olduvai, supports the hypothesis that scavenging, not hunting, was the major meat-procurement strategy of hominids between 2 and 1.7 million years ago. Data used to evaluate the hunting and scavenging hypotheses are derivedjom studring cut marks on Bed I bovids, comparing adaptations necessary for scavenging with those of ear& hominids, and a pa- leoecological reconstruction of Bed I carcass biomass, carnivore guild, and hominid foraging area.

ARLY HOMINID LIFE IS OFTEN RECONSTRUCTED AS BROADLY SIMILAR to that of E modern hunter-gatherers. Whether carrying (Hewes 1961, 1964) tool making (Dar- win 1871; Washburn 1960), food sharing (Isaac 1978, 1983), or seed eating (Jolly 1970) is seen as the crucial adaptation in hominid evolution, hunting and meat eating are often given a major place in early hominid life (Ardrey 1961, 1976; Bunn 1982, 1983b; Hill 1982; Isaac and Crader 1981; Tiger and Fox 1971; Washburn and Lancaster 1968; Wash- burn 1978). Although scavenging has been suggested, often as a behavioral transition between foraging for plant foods and hunting, it has only recently begun to be evaluated critically as a distinct and important adaptation (Binford 1981, 1984; Dunbar 1983; Isaac and Crader 1981; Isaac 1983; Potts 1982, 1984; Szalay 1975).

Previously, I presented preliminary evidence that hunting accompanied by systematic butchery and food sharing, as is typical of modern hunter-gatherers, is not supported by evidence from Bed I, Olduvai Gorge, Tanzania (Shipman 1984,1981; Potts and Shipman 1981; Shipman 1983). Bed I sites are appropriate for testing hypotheses about early hominid food-procurement strategies because of their antiquity (2-1.7 million years, Hay 1976), their numerous, well-preserved faunal remains associated with artifacts, and the well-documented geology, archeology, and taxonomy.

In this paper, I articulate and test hunting and scavenging hypotheses, using scanning electron microscope studies of cut marks and carnivore tooth marks on Bed I fossils and ecological, physiological, and behavioral studies of modern hominids and scavengers. Be- cause it is unclear which hominid species preserved in Bed I manufactured the Oldowan tool industry (Leakey 1971), I use the term “Oldowan” to refer to whichever hominid(s) were responsible for these activities.

The Hypotheses: Hunting versus Scavenging The hunting hypothesis postulates that a major factor in Oldowan life was the devel-

opment of hunting techniques and tools that fostered the development of central places or base camps; these served as temporary dwelling places and rendezvous at which animal foods were shared with or supplied to other members of the social group. Variants of this hypothesis are expressed in many works that emphasize the role of hunting and its correlated behaviors in human evolution, although scavenging is often mentioned briefly. As a heuristic device designed to clarify hypothesis evaluation, the hunting hypothesis

PATSHIPMAN is Assistant Prgessor, Department of Cell Biology and Anatomy, School of Mcdici’nc, Johns Hopkins University, Baltimore, M D 21205.

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28 AMERICAN ANTHROPOLOGIST [88, 1986

articulated here excludes any significant contribution to the diet by scavenging. “Hunt- ing” is defined as the intentional killing of animals larger than 5 kg by hominids using tools and weapons. The contribution of meat to the total diet obtained by hunting is un- quantified but “significant” (Isaac 1983:13), the rest of the diet being provided by gath- ered plant foods.

Behaviors closely associated with hunting, such as butchery and systematic disarticulation to permit food transport and sharing, are more readily identified in the fossil record than hunting per se. I explicitly assume here that Oldowan hunters engaged in these carcass-processing behaviors. It is theoretically possible that Oldowans hunted without engaging in any of these ancillary behaviors, in which case hunting would be nearly invisible archeologically or paleontologically. Propositions for testing the hunting hypothesis were generated from the extensive ethnographic literature about modern hunter-gatherers (e.g., Bicchieri 1972; Binford 1981; Coon 1971; Gifford 1977; Gould 1968, 1980; Lee and DeVore 1968, and references therein; Marks 1976; Marshall 1965; Service 1979; Turnbull 1965a, 196513; Winterhalder and Smith 1981, and references therein; Yellen 1977):

(1) If prey animals were disarticulated, then verified cut marks will occur near joints in frequencies (about 90%) comparable to those observed on more recent, butchered (i.e., disarticulated) prey remains.

(2) If both skin and meat were removed from bones, then skinning marks will be sub- stantially more frequent than meat-removal marks (75% vs. 25% respectively), because the skin is separated from distal limb elements overlaid by little flesh. Carnivores inter- ested primarily in obtaining meat produce a complementary pattern ofdamage, with over 75% of tooth marks occurring on meat-bearing bones (personal observation).

(3) If Oldowans were primarily hunters, then usually their cut marks will be overlaid by carnivore tooth marks, when sets of overlapping marks of different origin are found. A quantitative prediction about the frequency of overlapping cut marks and tooth marks cannot be made because there are no comparable data for assemblages known to have been hunted by stone-tool-wielding hominids and then scavenged.

The scavenging hypothesis proposes that the Oldowans were poor hunters, infre- quently capable of killing and defending their own prey. Instead, Oldowans relied mostly on scavenging to obtain meat, skin, or other substances from carcasses. Scavenging sup- plemented plant food foraging and did not provide the major portion of dietary intake, since such a situation is unknown among living mammals (Houston 1979). The contribution of scavenging to the diet is set at 33%, a figure chosen to indicate that scavenging is as significant a food-procurement strategy to Oldowans as it is to the most successful mammalian scavenger today, the spotted hyena. “Scavenging” refers both to obtaining meat or other substances from carcasses killed by other species and to carrion eating, or consuming partial or whole animals dead of nonpredatory causes.

Ethnographic data are lacking on predominantly scavenging peoples, so predictions for testing the scavenging hypothesis were generated by assuming, first, that the carcass- processing patterns typical of hunter-gatherers would be absent, and second, that scavenging, nonprimate species serve as appropriate analogues to a limited extent:

(1) If scavenging Oldowans’ access to carcasses was brief, then the clustering of cut marks near joints, indicative of systematic disarticulation, will be absent; the location of cut marks will closely resemble that of carnivore tooth marks.

(2) Since scavengers’ access to the choicest body parts are denied by the primary predators, Oldowans’ processing activities will occur more frequently (> 25%) on non-meat- bearing areas and less frequently (< 75%) on meat-bearing areas than those of carnivores.

(3) If hominids frequently scavenged from carnivore kills, then their cut marks will commonly overlie tooth marks when sets of overlapping marks are found.

(4) If scavenging was an important Oldowan behavior, then the physical or behavioral

Shipman] SCAVENGING OR HUNTING IN EARLY HOMINIDS 29

adaptations that distinguish modern scavenging species from predominantly hunting ones will be present among the Oldowans.

(5) If Oldowans practiced a scavenging and foraging lifestyle, then reconstruction of the Bed I , Olduvai, ecosystem will reveal sufficient herbivore biomass and predatory carnivores to provide carcasses for a scavenging hominid.

Binford (1984), Potts ( 1982), and Vrba (1980) suggest that scavenged assemblages show characteristic patterns of skeletal and age class representation. These criteria are not used because some studies (Bunn 1982; Shipman, Davis and Bosler, unpublished data) of scavenged assemblages do not show the suggested skeletal and age class representation patterns. In addition, Bed I assemblages show signs of a complex taphonomic history involving multiple agents (Potts and Shipman 1981) over at least several years (Potts 1982, 1984), which may have confused or obscured patterning created by any one agent.

Materials and Methods A comprehensive survey of damage on major limb bones of bovids ( N > 2,500 speci-

mens) from Bed I was undertaken. Bovids were selected as the most numerous and most probable prey species for any predator. Limb bones were utilized because they are abundant, well preserved, frequently identifiable to taxon, and often cut-marked at recent butchery sites (Bunn 1983a; Crader 1983; Guilday et al. 1962). All available bovid limb bones were inspected by eye and Iight microscope. All marks suspected ofbeing cut marks were replicated, as were a random sample of suspected toothmarks. All fossils identified as cut-marked by previous researchers were also replicated as were those bearing overlapping sets of marks, regardless of element or taxon. One to three areas on each of a total of 203 fossils were replicated and inspected using standard procedures (Rose 1983; Ship- man and Rose 1983a, 1983b). SEM inspection verified the identity of cut marks on 76 bones and carnivore tooth marks on 70 bones; many anatomical, preparator’s, and rodent gnawing marks were also identified.

Criticism (Bunn 1982, 1983b) that replication and SEM-inspection are unnecessary spurred a test of the accuracy of more gross means of mark identification. I reevaluated 230 marks identified by eye or light microscopy by Bunn, Potts, or Shipman as cut marks, without knowledge of the original identifications, using the SEM. Only 55%-60% of these showed the microscopic criteria diagnostic of cut marks. There was no significant variability in different observers’ success rates. It is highly unlikely that the SEM identifications are incorrect, since every known cut mark in a large control sample ( N > 1,000) inspected by SEM shows these microscopic features. The only taphonomic circumstance that produces marks microscopically identical to cut marks-trampling of bones in caves on top of sharp-edged rockfalls (Oliver 1984)-did not occur at Olduvai. Tooth marks, vascular grooves, and preparators’ marks were most commonly misidentified as cutmarks; rodent gnawing and heavy carnivore chewing are often readily identified at a gross level.

It is suggested that SEM use is not generally warranted if (1) the assemblage was created or modified by Homo sapiens, a species of known habits and (2) the observed patterning of presumed cut marks conforms to ethnographic reports for that region. In one such case (Villa and Shipman, unpublished data) there was over 90% concordance in identifications made by eye/light microscopy and SEM. However, more extensive SEM use is warranted in any study that relies on the sequence in which sets of overlapping marks were made.

Statistical evaluation of the Olduvai data require a control assemblage of bones hunted and butchered by hominids. Quantitative data for large, ethnographically documented assemblages with appropriate species are lacking; data from a Neolithic carcass-processing site (Prolonged Drift, Gifford et al. 1981) were used instead. Gross mark identifications by Gifford et al. (1981) were accepted, since criteria suggested above were met;


further, the assemblage lacks evidence of carnivore activity. Using data from Prolonged Drift, rather than a modern site, offers advantages. Prolonged Drift preserves stone tool cut marks rather than metal tool marks, which are more abundant (personal observation). Alsa, Gifford et al. (1981) provide detailed quantitative data on 296 cut marks on bovids similar to those at Olduvai, out of an identifiable subset (N = 3,700 bones) of the total assemblage (N > 20,000); these data are sufficient to establish clear patterns of carcass utilization. Finally, the interpretation of Prolonged Drift has met with little or no criticism.

Verified cut marks and tooth marks were classified as occurring in near joint or midshaft locations; when data were insufficient to determine which of these categories was appropriate, marks were assumed to occur in a near joint location (thus favoring the hunting hypothesis). Verified marks were classified as being located on meat-bearing bones (the proximal elements of each limb) or non-meat-bearing bones (the elements distal to the femur or humerus). Forty-two sets of overlapping marks were located and replicated, Only 13 sets included both cut marks and carnivore tooth marks and showed clear indications of the sequence in which the marks were made (Shipman and Rose 1983a).

Literature on modern African ecosystems was used to identify adaptations and ecological prerequisites to successful scavenging, as distinct from hunting. Primary data on Af- rican animals are derived in general from Schaller (1968, 1972), Kruuk (1972, 1976), Bertram (1973, 1975), Estes and Goddard (1967), Frame and Frame (1976), Rudnai (1973), and Van Lawick-Goodall and Van Lawick (1970). Useful reviews and analyses are found in Bertram (1979), Curio (1976), Eaton (1979), Ewer (1973), Houston (1979), Nowak and Paradiso (1983), and C. Pennycuick (1971, 1979). For ease of discussion below, references will be cited only for specific data on attributes of carnivore and avian behavior.

In addition, data on Olduvai ecology and fauna, on various metabolic relationships, and on Oldowan population densities were used in reconstructions. All estimates and calculations were based as firmly as possible on documented information and established energetic and ecological principles, but the results may not be accurate much past the order of magnitude. All estimates were made conservatively, to test the scavenging hypothesis stringently. In addition, it was established a priori that the prediction of feasibility would be upheld only if available carcass biomass generously exceeded consumption.

Results and Discussion: Cut Mark Studies

The first prediction of each hypothesis depends upon the distribution of cut marks on the Olduvai fossils in terms of near joint and midshaft locations. Chi-square tests reveal that the Olduvai cut marks are distributed significantly differently from the Prolonged Drift cut marks (Table 1) and do not cluster near joints as predicted by the hunting hypothesis. In contrast, the Olduvai cut mark distribution is indistinguishable from that of the 70 carnivore tooth marks, as predicted by the scavenging hypothesis. These results are not significantly altered by the exclusion ofcut marks ofambiguous location (assumed to be near joint) from the sample.

The second predictions of the two hypotheses were both fulfilled (p < 0.05 in each case: Table 2) but are not mutually exclusive. The results could be interpreted equally validly to mean either that hominids utilized carcasses opportunistically (scavenged) or that they utilized carcasses fully and systematically (hunted).

Of the 13 overlapping sets of marks, 8 showed that the carnivore tooth marks were made first and the cut marks were made second; in the remaining 5 cases, the situation was reversed. These data are direct, if limited, evidence that Oldowans scavenged from carnivore kills on occasion. These results do not differ statistically from a hypothetical situation in which 6.5 cut marks overlie tooth marks and 6.5 tooth marks overlie cut


Table 1 Distribution of cut marks and tooth marks on Olduvai bovids relative to joints compared with that of cut marks from Prolonged Drift.

Near joint Midshaft Significance (a) Olduvai cut marks 26 34 avs. b: chiz = 86.3

1 degree of freedom p c 0.001*

p c 0.001*

1 degree of freedom p > 0.05

(b) Prolonged Drift 272 24 b vs. c: chiz = 125.0 1 degree of freedom

(c) Olduvai tooth marks 28 42 a vs. c: chiz = 0.143

*Indicates level of probability accepted as significant.

Table 2 Distribution of cut marks and tooth marks on Olduvai bovids relative to major muscle masses compared with that at Prolonged Drift.

Meat-bearing Non-meat- bones bearing bones Significance

(a) Olduvai cut marks 22 38 avs. b: chiz = 2.5 1 degree of freedom p > 0.05

(b) Prolonged Drift 77 217 b vs. c: chi2 = 50.9 1 degree of freedom p C 0.005*

(c) Olduvai tooth marks 41 13 a vs. c: chiz = 17.9 1 degree of freedom p C 0.005*

~ ~~ ~ ~

*Indicates level of probability accepted as significant.

marks. These results do differ significantly (chi-square = 4.4, 1 d.f., p C 0.05) from a hypothetical situation in which all 13 tooth marks overlie cut marks, the extreme case expected if Oldowans only hunted.

In general, the cut mark data support the scavenging hypothesis and do not support the hunting hypothesis as stated here. A possibility that cannot be eliminated is that hunting was carried out by Oldowans but that neither disarticulation nor transport or sharing of food occurred. I can see no means to transform this possibility into a testable hypothesis at present.

Results and Discussion: Adaptations to Scavenging The Serengeti Plains ecosystem, adjoining Olduvai Gorge, is inhabited by nine species

of medium- and large-sized carnivores: the lion, Panthera Leo; the spotted hyena, Crocuta crocuta; the leopard, Panthera pardus; the cheetah, Acinonyx jubatur; the striped hyena, Hyaena hyuena; the hunting dog, Lycaonpictus; and three jackals, Canis mesomelas, C. adustus, and C. aureus. Differences among the three jackals are poorly documented, so they are treated as a single species (Canis sp.) here. Only the cheetah and the hunting dog are almost never observed to scavenge. Each of the others scavenges to a greater or lesser extent (up to about 33%; Bertram 1979:222-223). In general, when the migratory herbivores are absent, these part-time scavenging species turn to alternative food sources (fruit, hunted prey); when the migratory herds are present, carcasses are abundant and


these species scavenge more frequently. In short, they scavenge when they can and hunt or forage when they must. This flexibility suggests that hunting and scavenging lie along a behavioral continuum; nonetheless, there are powerful adaptive differences between those that do and do not scavenge. Since no living mammal scavenges for all of its food, I discuss the only purely scavenging vertebrates in Africa today: species of raptors, re- ferred to here collectively as “vultures,” that are obligate or nearly exclusive scavengers. For analysis, species were divided into three categories that represent a gradient from hunting to scavenging: (1) predatory carnivores (cheetah, hunting dog) that rarely scavenge; (2) scavenging carnivores (jackal, striped and spotted hyenas, leopard, lion) that scavenge part-time; (3) obligate or exclusive scavengers (the vultures). Features typical of each group were sought from the literature, Houston (1979) being especially useful.

The major adaptation enabling the vultures to be exclusive scavengers is their ener- getically inexpensive mode of locomotion: flying. Since carcasses are always less abundant than potential prey, only a species that can cover large areas cheaply is assured of finding enough c:arcasses. Although the cost of locomotion is important to scavengers, its speed is not. Predatory carnivores are consistently faster, in some sense, than scavenging ones. Vultures lessen the energetic costs oflocomotion, but also their speed, by gliding at the prevailing wind speed. In short, speed is a trade-off for cost and endurance; the former is more important to predators or hunters, the latter to scavengers.

Perhaps the second most important requisite of a successful scavenger is an adaptation for locating carcasses. In vultures, it is a secondary benefit of their mode of locomotion, which improves their vantage point, combined with keen eyesight. The most successful mammalian scavenger, the spotted hyena, responds more rapidly to the sight of circling vultures than do other carnivores (Kruuk 1972) and has a keen sense of smell (Ewer 1973).

The third adaptation is a means of dealing with interference competition over carcasses. Often, primary predators are forced either to defend a carcass or to relinquish it to scavengers. Large body size or sociality are important determinants of success in interference competition (Eaton 1979); small-bodied scavengers usually specialize in stealth and avoidance behaviors. The two strategies can be simply characterized as being either a “bully” or a “sneak.” Predatory carnivores’ characteristics contrast sharply with those of scavengers. Both cheetahs and hunting dogs are of intermediate size, and both frequently lose interference encounters. Further, hunting dogs are so highly social that it is hard to scavenge sufficient food for the group. Predatory carnivores maximize the meat obtained per unit energy expended in a chase by adapting for speed in pursuit and in carcass processing; scavenging carnivores maximize either the number of carcasses they can appropriate (the bully strategy) or the amount of meat they can scavenge without risking appropriation (the sneak strategy).

The fourth adaptation to scavenging is utilizing a reliable, alternative food source. Larger scavenging carnivores hunt when scavenging fails; smaller ones rely on fruit and/ or insects for the bulk of their diet.

Finally, many living scavengers apparently possess physiological or behavioral adaptations for dealing with rotten food, but these would be undetectable in the fossil record.

The hominid fossil record from Bed I was examined to see if the four detectable adaptations were present. All of the Bed I hominids possess clear and unmistakeable adaptations for bipedalism (Johanson and White 1979; Johanson et al. 1982; Leakey and Hay 1979; Lovejoy et al. 1973; Lovejoy 1974; McHenry 1978, 1982; McHenry and Temerin 1979; Robinson 1972; Stern and Susman 1983; Susman and Stern 1982; Zihlman 1978; Zihlman and Brunker 1979). It has often been overlooked that, at speeds of 1.1 to 1.7 m/ sec, bipedal walking is empirically at least as efficient as quadrupedal walking, if body size, speed, and distance are held constant (Fedak and Seeherman 1979; Taylor et al. 1982; Taylor 1977 and personal communication). Bipedal walking is also more efficient than quadrupedal walking as practiced by modern pongids (Rodman and McHenry 1980). Thus, bipedal walking fulfills the locomotor needs of a scavenger.


Evidence for efficient carcass location is also seen. Bipedalism inevitably raised the horninid’s head and markedly improved its ability to spot items on the ground, such as carcasses (e.g., Dart 1959; Howells 1959). Arguments that australopithecines and Homo habilis are adapted to tree climbing and arboreality in addition to bipedalism (McHenry 1978; Prost 1980; M. D. Rose 1984; Senut 198 1; Stern and Susman 1983; Susman and Stern 1979, 1982; Vrba 1979) suggest an additional adaptation for improving vantage point.

To reconstruct strategies for dealing with interference competition, knowledge of body size is needed. Estimates for Oldowans range from about 18 kg to 70 kg (Brain 1981; Cronin et al. 1981; Holloway 1978; McHenry 1976; Steudel 1980). I take 35 kg to represent mean Oldowan body size here, since this figure occurs within the separate ranges for each hominid species. All modern scavenging carnivores of comparable size or smaller use a sneak strategy. Retaining arboreal adaptations enabled Oldowans to lessen competition further by retreating into the trees to consume scavenged bits (see Brain 1970, 1981). In addition, the use of stone tools can be viewed as a direct adaptation to speedy removal of substances from carcasses. Thus, two adaptations suitable for a sneak scavenger were present. Scavenging in social groups is also possible, but the cut-mark data indicate this occurred rarely, briefly, or not at all. Binford (1984) suggests temporal strategies might lessen competition with largely crepuscular or nocturnal carnivores; this plausible strategy is, unfortunately, difficult to test with evidence from the fossil record.

The most probable alternative food source for Oldowans was fruit, judging from dental microwear data (Walker personal communication; Walker 1980, 1981). This pattern of scavenging and frugivory is documented for striped hyenas, which are of comparable body size to Oldowans (Kruuk 1976). Since the locomotor needs of scavenging are the same as those of foraging for unpredictably distributed, stationary resources, such as fruit, an individual can easily forage and scavenge simultaneously.

In summary, all adaptations ofscavengers likely to be observed in the fossil record were present in Oldowans.

Results and Discussion: Ecological Feasibility Was the biomass in ancient Olduvai suficient to make scavenging by Oldowans a fea-

sible strategy? The first consideration is that the Bed I carnivore guild was larger than today’s. In

addition to rough equivalents of the modern Serengeti carnivores, Bed I had two extra species of large, sabre-toothed cats, notable for their highly specialized, slicing teeth (Walker 1984). These were highly predatory carcass providers adapted for meat eating, not scavenging (Ewer 1973; Savage 1978); they were formidable opponents in interference competition (Brain 1981; Van Valkenburgh personal communication).

However, herbivore biomass was also larger. Faunal, geologic, isotopic and palynol- ogic studies (Gentry and Gentry 1978a, 1978b; Hay 1976; Ceding et al. 1977; Bonnefille 1977 [cited in Potts 19821 ) all suggest Bed I rainfall exceeded current levels (800 mm/ yr; Norton-Griffiths et al. 1975) by 100-200 mm/yr. Since herbivore biomass in Africa is a function of annual rainfall (Coe et al. 1976), it can be estimated that rainfall of 900- 1,000 mm/yr in the Serengeti would produce a 100%-400°/~ increase in prey biomass over current levels if the habitat remained relatively open. Open habitat was likely, since the Serengeti soils inhibit tree growth both now and in Bed I times (Sinclair 1979; sHay 1976). A realistic estimate of Bed I herbivore biomass is more than that of the Serengeti today, or about 12,300 kg/km2 (East 1984). This reconstructed density is surpassed in the modern Serengeti during the rainy season (L. Pennycuick 1975) and is well within the realm of possibility.

The annual Bed I carcass biomass, expressed here as kilograms of dead herbivores (kilocarcasses or kg-c) per square kilometer, is estimated using the average annual mortality rate of 16% across all ungulate species (Houston 1979) for the Serengeti today. A


similar mortality rate in Bed I times would yield 1,968 kg-c/km2 per year. How many kg- c/km2 is an Oldowan likely to discover?

Foraging radius (r) is defined as the maximum distance that can be traveled by an animal from a food source to another point (base camp, den, sleeping tree, waterhole, tool cache, etc.) without undergoing net energy loss on the trip back or onward to a food source. C. Pennycuick’s basic equation (1979:167) is modified to allow 12 hours daily for foraging, since Oldowans were almost certainly diurnal.

eV ( 1 ) r = 4 Em + 4kV

where e = the energy extracted from a full gut load V = velocity of travel in meters per second Em = basal metabolic rate (a function of m, or body size) k = constant representing the energy required to propel an animal a unit distance, based on the metabolic cost of locomotion (Elz) in addition to Em.

Oldowan body weight is set at 35 kg. e varies between about 82,000 joules/kg of con- sumer’s body weight for grass eaters to at least 328,000 joules/kg for meat eaters; fruit eaters probably fall between these two values (C. Pennycuick 1979). Two alternatives are modeled. On pure scavenging trips, e = 11,480,000 joules/individual. In mixed fruit- foraging (60%) and scavenging (33%) trips, e = 5,682,600 joules/individual at a minimum. Oldowan walking velocity is set at 1.1 m/sec (the low end of the optimally efficient range for modern hominids: Margaria et al. 1963), since smaller hominids’ most efficient velocity is lower than that of larger hominids. Basal metabolic rate (Em) is derived following C. Pennycuick (1979:168): (2) Em = 4.8 mo.74

Em = 66.7 watts for a 35-kg hominid Em = basal metabolic rate in watts m = body weight in kilograms

where

k is no larger than the empirically determined cost of walking at 1.1 m/sec for modern humans twice as large as Oldowans (100.5 joules/kg/m: Taylor 1977; Margaria et al. 1963) and is probably smaller. k is derived (C. Pennycuick 1979:165):

V (3) k = -

El2 k = 91.4

where Elz = incremental cost of locomotion (cost of walking) Substituting these values into equation (1) yields the values of r for a lone Oldowan

and for an Oldowan mother carrying a 10-kg nursing infant (Table 3). The latter circumstance is modeled as a worst-case scenario. Her metabolic rate is increased to 100.5 watts by lactation (Crampton and Lloyd 1959; Portman 1970), but e, V, and k (Goldman and Iampietro 1962) do not change. If an area of radius r were effectively searched annually, by covering a 1” sector for each of 360 days (leaving 5 days/yr for repeat trips or illness), then the foraging area and the total number of kilocarcasses encountered (kg-ctotal) can be calculated (Table 4).

Whether or not kg-ctotal were sufficient for a scavenging Oldowan depends on other species’ consumption, the Oldowan’s dietary needs, and the density of Oldowans within the foraging area.

A crude estimate of kg-ceaten by nonhominids is derived from modern data (Houston 1979). Today, the mammalian predators eat only 35% of the yearly carcass biomass, with vultures taking another So%, and the rest being either wasted or consumed by inverte-


Table 3 Energy extracted from a full gut load (e) and foraging radius (r) of Oldowans, at varying rates of scavenging.

~~

Value of c Foraging radius, Time spent daily (35 ka Oldowan) T traveling. 2r

Lone Oldowan 100% scavenging 1 1,480,000 joules 18.9 km 9 hr, 36 min 33% scavenging 5,682,600 joules 9.3 km 4 hr, 42 min

100% scavenging 1 1,480,000 joules 15.7 km 7 hr, 54 min 33% scavenging 5,682,600 joules 7.8 km 3 hr, 54 min

Oldowan with infant

Table 4 Kilocarcasses encountered by an Oldowan during foraging trips yearly and daily.

Foraging Foraging area radius r yearly (daily) Kilocarcasses in km in km' yearly (daily)

Lone Oldowan 100% meat 18.9 1122 (3.1) 2,208,096 (16.8) 33% meat 9.3 272 (0.76) 535,296 (4.1)

100% meat 15.7 774 (2.2) 1,523,232 ( 1 1.6) 33% meat 7.8 191 (0.53) 375,888 (2.9)

Oldowan with infant

Table 5 Acquisition rates for a lone Oldowan on a pure scavenging trip (100% meat).

Maximum intake Minimum intake (0.5 kg) (0.2 kg)

Foraging area 3.1 kmz 3.1 km' Kg-ctotal 16.8 16.8 AR 3 '/o 1 Yo ARgroup 18% 7 Yo

brates. East's (1984) work shows that the relative proportions of herbivores and carnivores remain nearly constant with increased rainfall in savannahs like the Serengeti. Thus, the percentage consumption by modern carnivores or their equivalents remained constant over the last 2 million years. Avian consumption is assumed to also scale with rainfall, accounting for about 30% of the dead herbivore biomass. Invertebrate consumption, now at about 35%, varies with food availability; thus, that 35% is the maximum available for hominid scavenging.

Meat intake of spotted hyenas (0.66 kg of scavenged meat/individual/day: Kruuk 1972) and !Kung San (0.23 kg of meat/individual/day: Lee 1968) were used to set probable limits on intake by Oldowans. Because a lone Oldowan's metabolic rate was about 75% of these species' rates, these limits are scaled down to 0.5 and 0.2 kg meadindivid- ual/day (Garland 1983). The Oldowan mother's intake was higher: 0.8 and 0.3 kg meat/ individuaVday. Meat intake by other Oldowans had only a small effect. Early hominid densities are suggested to fall between 0.001 and 2 individuals/km2 when mixed diet (om- nivory) is postulated (Boaz 1979; Martin 1981; Walker and Leakey 1978).

The daily acquisition rate (AR) needed by an Oldowan to maintain life is calculated


Table 6 Acquisition rates for a lone Oldowan on a mixed foraging-scavenging trip (33% meat).

Maximum intake Minimum intake (0.5 kg) (0.2 kg)

Foraging area Kg-ctotal AR

0.76 kmz 4.1 12%

0.76 km2 4.1 5%

ARgroup 19% 7 yo

Table 7 Acquisition rates for a lactating Oldowan for a pure scavenging trip (100O/0 meat).

Maximum intake Minimum intake (Mother: 0.8 kg) (Others: 0.5 kg)

(Mother: 0.3 kg) (Others: 0.2 kg)

Foraging area 2.2 km2 2.2 km2 Kg-ctotal 11.6 11.6 AR 7 yo 3 yo ARgroup 22% 8%

Table 8 Acquisition rates for a lactating Oldowan for a mixed foraging-scavenging trip (33% meat).

Maximum intake Minimum intake (Mother: 0.8 kg) (Others: 0.5 kg)

(Mother: 0.3 kg) (Others: 0.2 kg)

Foraging area 0.53 km2 0.53 km2 Kg-ctotal 2.9 2.9 AR 28% 10% ARgroup 29% 1 1 O/O

as a percentage of kg-ctotal encountered within its foraging radius; ARgroup is the total needed by Oldowans living at a maximum density and sharing a foraging radius (Tables

A lone Oldowan needed to obtain 1%-12% of the kilocarcasses available for scavenging in its daily foraging area if no other hominids were present or 7%-9% if others shared the area. In these cases, acquisition rates were much lower than 35%, indicating that scavenging by Oldowans was feasible. Further, the acquisition rates are so low that there is a wide margin for error in the estimates and assumptions without rendering scavenging unfeasible for an Oldowan (contra Schaller and Lowther 1969).

The case most closely approaching the limits of the system is that of an Oldowan mother with nursing infant (Tables 7-8). If she had the maximum postulated meat intake, and if she lived in an area of high hominid density, she had an AR of 29%. Given that all estimates were made to test the feasibility of the scavenging hypothesis severely, while remaining within the bounds of reason, it is remarkable that the AR remains below 35% even in this most difficult situation. This reconstruction does not require either co- operative social behavior or provisioning of females and offspring. It is concluded that the predictions of feasibility are met.

5-8) *


Conclusions: Scavenging, the Home Base Hypothesis and Human Evolution All tests of predictions of the scavenging hypothesis given here are fulfilled by a gen-

erous margin. It is concluded that the scavenging hypothesis is not refuted and is worthy of additional investigation.

The idea that scavenging may have been a major food-procurement strategy in Bed I times has broader implications. The first of these is that it casts doubt on the idea that sites represent central places, home bases, or camp sites that were the focus of transport and sharing of food. The cut-mark evidence strongly suggests that systematic disarticulation to enable transport and sharing of carcasses did not occur. The feasibility data suggest that provisioning, food sharing, and division of labor are not necessarily intrinsic to strategies involving utilization of carcasses. Additional problems with the familiarly human interpretation of Bed I sites arise because of the many biological and ecological differences between Oldowans and modern hunter-gatherers. Since Oldowans were small and relatively small-brained, lacked fire, projectile weapons, and domestic dogs, and lived in areas with a higher large carnivore density than any modern African habitat, the danger of sleeping and caring for offspring near carcasses was considerably greater for Oldowans than for modern humans (Shipman 1983). In short, it is difficult to reconcile this information with the notion that Bed I sites were base camps.

Other evidence leads to questions about the home base hypothesis, too. Potts (1982, 1984) presents other evidence that competition from carnivores seriously restricted 01- dowan access to carcasses and made the time spent in carcass-processing areas likely to be brief. He reports that the disparate weathering on Bed I bones indicates either occu- pation over four or more years at each site or repeated reoccupation; neither of these behaviors is common among modern hunter-gatherers.

If Bed I sites are not base camps, what mechanism accounts for the abnormally dense accumulations of bones associated with stone tools? Two possibilities that are not mutually exclusive are suggested. The first is that Bed I sites represent safe areas, such as trees, to which scavenged items were carried. Bones and tools accumulated as these safe areas were used repeatedly. Unlike hunting, transport of scavenged items does not in- variably require disarticulation with tools, since body parts or scraps separated from the carcass by primary predators are prime targets for scavenging. The second possibility, articulated by Potts (1982, 1984), is that these sites represent stone caches, to which resources were taken for processing. Although Potts assumes random distributions of both caches and faunal resources, and I make a similar assumption about carcasses, neither carcasses nor faunal resources are randomly distributed (Blumenschine 1984; Behrens- meyer and Dechant-Boaz 1980). The discrepancy between our models and reality means that Oldowans could have improved the frequency with which they encountered carcasses/faunal resources by utilizing their habitat selectively. The stone cache hypothesis is especially congruent with the scavenging hypothesis if caches were placed or used more frequently near features that favored scavenging. Such features might include trees suitable for climbing, or waterholes, because of the high frequency ofcarcasses and the habits of carnivores (Binford 1984).

A major site from a later time period has been interpreted as preserving scavenged remains: Klasies River Mouth (KRM), reinterpreted by Binford (1984) following upon quite different interpretations by Klein (1981 and references therein). Whichever interpretation is correct, the KRM data differ in interesting ways from the Bed I data. First, at KRM there was differential treatment of bovids according to size class. Binford main- tains that larger bovids (size classes IV-V) were scavenged, whereas smaller ones (size classes 1-111) were hunted. This pattern is not apparent at Olduvai: the sample of cut- marked, apparently scavenged bones includes only one larger bovid specimen. Second, the KRM scavenged material was apparently processed heavily for marrow, whereas the Olduvai bones were not intensively utilized and modified for marrow extraction. Potts (1984:344) concurs, stating that Olduvai bones show “incomplete processing . . . [and]


suggest that hominids abandoned considerable portions of meat and marrow at each site.” Finally, Binford (1984~86) remarks on the inflexible behavior of KRM hominids in scavenging: “an almost ‘stimulus-response’ structure of behavior.” My impression is that the Olduvai data do not reveal strong patterning or routinized treatment of remains, but rather more opportunistic and haphazard processing. These differences may indicate either that scavenging behaviors changed as hominids evolved or that the interpretation of one of the two faunas (KRM or Olduvai) as scavenged is inaccurate.

Finally, why bipedalism arose is a classic issue. The striking congruency between the attributes of bipedalism, as analyzed here, and the locomotor needs of scavengers might suggest to some that bipedalism is actually an adaptation, not an exaptation (Gould and Vrba 1982), to scavenging. If it is to be concluded that the origins of bipedalism and scavenging are causally related, one of two difficulties must be surmounted. Either the earliest evidence for toolmaking must be pushed back to more closely approximate that of bipedalism or it must be postulated that effective scavenging was possible without dental or technological adaptations for carcass processing.

Acknowledgments. This work was funded by the National Science Foundation (BNS 80- 1397 and 80-2-1397) and from the Boise Fund. I appreciate the assistance and cooperation of the President’s Office of Kenya (permit OP. 13/001/6C70), the Government ofTanzania and the staff of the Na- tional Museums of Kenya. Especial thanks go to M. D., R. E., and M. E. Leakey for their help. This paper benefited greatly from the advice and discussion ofJ. Buikstra, M. Cartmill, G. Isaac, R. Lewin, R. Potts, M. Schoeninger, R. Smith, M. Teaford, R. Taylor, B. Van Valkenburgh, A. Walker, and J. Rose. J. Rose and B. Coe provided technical assistance.

References Cited Ardrey, R.

1961 African Genesis: A Personal Investigation into the Animal Origins and Nature of Man.

1976 The Hunting Hypothesis: A Personal Conclusion Concerning the Evolutionary Nature of New York: Dell.

Man. New York: Atheneum Press. Behrensmeyer, A. K., and D. E. Dechant-Boaz

1980 The Recent Bones ofAmboseli Park, Kenya, in Relation to East African Paleoecology. In Fossils in the Making. A. K. Behrensmeyer and A. P. Hill, eds. Pp. 72-93. Chicago: University of Chicago Press.

Bertram, B. C. R. 1973 Lion Population Regulation. East African Wildlife Journal 1 1:215-225. 1975 Weights and Measures of Lions. East African Wildlife Journal 13:141-143. 1979 Serengeti Predators and Their Social Systems. In Serengeti: Dynamics of an Ecosystem.

A. R. E. Sinclair and M. Norton-Griffiths, eds. Pp. 221-248. Chicago: University of Chicago Press.

Bicchieri, M. D., ed.

Binford, L. R. 1972 Hunters and Gatherers Today. New York: Holt, Rinehart & Winston.

1981 Bones: Ancient Men and Modern Myths. San Francisco: Academic Press. 1984 Faunal Remains from Klasies River Mouth. San Francisco: Academic Press.

1984 Scavenging in the Serengeti. Anthroquest 28:ll-12.

1979 Early Hominid Population Densities: New Estimates. Science 206:592-595.

1977 Etudes palynologiques des depots Plio-Pleistocene (Beds I and 11). National Geographic

Blumenschine, R. J.

Boaz, N. T.

Bonnefille, R.

Society Report. Brain, C. K.

1970 New Finds at the Swartkrans Australopithecine Site. Nature 225:1112-1119. 1981 The Hunters or the Hunted? An Introduction to African Cave Taphonomy. Chicago:

University of Chicago Press.

Shipman] SCA VENCING OR HUNTING IN EARLY HOMlNIDS 39

Bunn, H. 1982 Meat-eating and Human Evolution. Ph.D. thesis, University of California, Berkeley. 1983a Comparative Analysis of Modern Bone Assemblages from a San Hunter-Gatherer

Camp in the Kalahari Desert, Botswana, and from a Spotted Hyena Den near Nairobi, Kenya. In Animals and Archaeology, Vol. 1. J. Clutton-Brock and C. Grigson, eds. Pp. 143-148. Lon- don: British Archaeological Reports.

1983b Evidence on the Diet and Subsistence Patterns of Plio-Pleistocene Hominids at Koobi Fora, Kenya, and at Olduvai Gorge, Tanzania. In Animals and Archaeology, Vol. 1. J. Clut- ton-Brock and C. Grigson, eds. Pp. 2 1-30. London: British Archaeological Reports.

Ceding, T., R. Hay, and J. O’Neil 1977 Isotopic Evidence for Dramatic Climatic Changes in East Africa during the Pleistocene.

Nature 267:137-138. Coe, M. J., D. H. Cumming, and J. Phillipson

1976 Biomass and Production of Large African Herbivores in Relation to Rainfall and Primary Production. Oecologia 22:34 1-354.

Coon, C. S.

Crader, D. C. 197 1 The Hunting Peoples. Harmondsworth, England: Pelican Books.

1983 Recent Single-carcass Bone Scatters and the Problems of ‘Butchery’ Sites in the Archae- ological Record. In Animals and Archaeology, Vol. 1. J. Clutton-Brock and C. Grigson, eds. Pp. 107-141. London: British Archaeological Reports.

Crampton, E., and L. Lloyd 1959 Fundamentals of Nutrition. San Francisco: W. H. Freeman.

Cronin, J. E., N. T. Boaz, C. S. Stringer, and Y. Rak 1981 Tempo and Mode of Hominid Evolution. Nature 292:113-122.

Curio, E. 1976 The Ethology of Predation. Berlin: Spring-Verlag.

Darwin, C. 187 1 Descent of Man. London: John Murray & Sons.

Dart, R. A. 1959 Adventures with the Missing Link. Philadelphia: Institutes Press.

Dunbar, R. I. M. 1983 Theropithecines and Hominids: Contrasting Solutions to the Same Ecological Problem.

East, R. 1984 Rainfall, Soil Nutrient Status and Biomass of Large African Savannah Animals. African

Journal of Human Evolution 12:647-658.

Journal of Ecology 22(4):245-270. Eaton, R. L.

1979 Interference Competition among Carnivores: A Model for the Evolution of Social Behav- ior. Carnivore 29-16.

Estes, R., and J. Goddard

agement 31( 1):52-70. 1967 Prey Selection and Hunting Behavior of the African Wild Dog. Journal of Wildlife Man-

Ewer, R. F.

Fedak, M. A,, and H. J. Seeherman 1973 The Carnivores. I thaca: Cornell University Press.

1979 Re-appraisal of Energetics of Locomotion Shows Identical Cost in Bipeds and Quad- rupeds including Ostrich and Horse. Nature 282:713-716.

Frame, L. H., and G. W. Frame

Garland, T. 1976

1983

Wild Dogs of the Serengeti. African Wildlife Foundation Newsletter (Nairobi) 11 (3): 1-6.

Scaling the Ecological Cost of Transport to Body Mass in Terrestrial Mammals. Amer- ican Naturalist 121:571-587.

Gentry, A. W., and A. Gentry 1978a Fossil Bovidae (Mammalia) of Olduvai Gorge, Tanzania, Part I. Bulletin of the British

1978b Fossil Bovidae (Mammalia) ofOlduvai Gorge, Tanzania, Part 11. Bulletin of the British Museum of Natural History (Geology) 2 9 ( 4 ) : 2 8 W .

Museum of Natural History (Geology) 30( 1): 1-83.


Gifford, D. 1977 Observations of Modern Human Settlements as an Aid to Archaeological Interpretation.

Ph.D. dissertation, University of California, Berkeley. Gifford, D. P., G. L1. Isaac, and C. M. Nelson

1981 Evidence for Predation and Pastoralism at Prolonged Drift: A Pastoral Neolithic Site in Kenya. Azania 15:57-108.

Goldman, R. F., and P. F. Iampietro

Could, R. A. 1962 Energy Cost of Load Carriage. Journal of Applied Physiology 17:675-676.

1968 Living Archaeology: The Ngatatjara of Western Australia. Southwest Journal of Anthro-

1980 Living Archaeology. Cambridge: Cambridge University Press.

1982 Exaptation: A Missing Term in the Science of Form. Paleobiology 8:4-15.

1962 Aboriginal Butchering Techniques at the Eschelman Site (36LA12), Lancaster County,

Hay, R. 1976 Geology of the Olduvai Gorge: A Study of Sedimentation in a Semiarid Basin. Berkeley:

pology 24: 104-122.

Could, S. J., and E. S. Vrba

Guilday, J. E., P. W. Parmalee, and D. P. Tanner

Pennsylvania. Pennsylvania Archaeology 32:59-83.

University of California Press. Hewes, G. W.

196 1 Food Transport and the Origin of Hominid Bipedalism. American Anthropologist

1964 Hominid Bipedalism: Independent Evidence for the Food-carrying Theory. Science 63:687-7 10.

146:4 1 €A 18. Hill, K.

1982 Hunting and Human Evolution..lournal of Human Evolution 11:521-544. - - Holloway, R. L.

1978 Problems of Brain Interpretation and African Hominid Evolution. In Early Hominids of Africa. C. J. Jolly, ed. Pp. 379401. New York: St. Martin’s Press.

Houston, D.C. 1979 The Adaptations of Scavengers. In Serengeti: Dynamics of an Ecosystem. A. R. E. Sinclair

and M. Norton-Griffiths, eds. Pp. 263-286. Chicago: University of Chicago Press. Howells, W.

Isaac, G. L1. 1959 Mankind in the Making: The Story of Human Evolution. Garden City, NY: Doubleday.

1978 The Food-sharing Behavior of Proto-human Hominids. Scientific American 238:9&108. 1983 Bones in Contention: Competing Explanations for the Juxtaposition of Early Pleistocene

Artifacts and Faunal Remains. In Animals and Archaeology, Vol. 1. J. Clutton-Brock and C. Grigson, eds. Pp. 3-19. London: British Archaeological Reports.

Isaac, G. L l . , and D. Crader 1981 To What Extent Were Early Hominids Carnivorous? An Archaeological Perspective. In

Omnivorous Primates: Gathering and Hunting in Human Evolution. R. S. 0. Harding and G. Teleki, eds. Pp. 37-103. New York: Columbia University Press.

Johanson, D. C., and T. D. White

Johanson, D. C., M. Taieb, and Y. Coppens 1979

1982

A Systematic Assessment of Early African Hominids. Science 203:321-330.

Pliocene Hominids from the Hadar Formation, Ethiopia (1973-1977): Stratigraphic, Chronologic and Paleoenvironmental Contexts, with Notes on Hominid Morphology and Sys- tematics. American Journal of Physical Anthropology 57:373402.

Jolly, C. J. 1970 The Seed-eater Hypothesis: A New Model ofHominid Differentiation Based on a Baboon

Analogy. Man 55-20. Klein, R. G.

198 1 Stone Age Predation of Small African Bovids. South African Archaeological Bulletin

Kruuk, H. 1972 The Spotted Hyena: A Study of Predation and Social Behavior. Chicago: University of

1976 Feeding and Social Behavior of the Striped Hyaena (Hyaena vulgaris Desmarest). East Af-

36:55-65.

Chicago Press.

rican Wildlife Journal 14(2):91-112.

Shipman] SCA VENGING OR HUNTING IN EARLY HOMINIDS 41

Leakey, M.D.

Leakey, M. D., and R. L. Hay 1971

1979

Lee, R. B. 1968 What Hunters Do for a Living, or, How to Make Out on Scarce Resources. In Man the

Lee, R. B., and I. DeVore, eds.

Lovejoy, C. 0.

Lovejoy, C. O., K. G. Heiple, and A. H. Burstein

Margaria, R., P. Cerretelli, P. Aghemo, and G. Sassi

Marks, S. A.

Marshall, L.

Olduvai Gorge, Vol. 3. London: Cambridge University Press.

Pliocene Footprints in the Laetolil Beds at Laetoli, Northern Tanzania. Nature 278:317- 323.

Hunter. R. E. Lee and I. De Vore, eds. Pp. 30-48. Chicago: Aldine.

1968 Man the Hunter. Chicago: Aldine.

1974 The Gait ofAustralopithecines. Yearbook of Physical Anthropology 41:191-215.

1973 The Gait of Australopithccus. American Journal of Physical Anthropology 38:757-780.

1963 Energy Cost of Running. Journal of Applied Physiology 18:367-370.

1976 Large Mammals and a Brave People. Seattle: University of Washington Press.

1965 The !Kung Bushmen of the Kalahari Desert. In Peoples of Africa. J. L. Gibbs, ed. Pp. 241-278. New York: Holt, Rinehart & Winston.

Martin, R. A.

McHenry, H. M. 1981 On Extinct Population Densities. Journal of Human Evolution 10:427-428.

1976 Early Hominid Body Weight and Encephalization. American Journal of Physical An-

1978 Fore- and Hindlimb Proportions in Plio-Pleistocene Hominids. American Journal of

1982 The Pattern of Human Evolution: Studies on Bipedalism, Mastication, and Encephali-

thropology 45:77-84.

Physical Anthropology 4 3 : 3 9 4 .

zation. Annual Review of Anthropology 11:151-173. McHenry, H. M., and L. A. Temerin

1979 The Evolution of Hominid Bipedalism: Evidence from the Fossil Record. Yearbook of Physical Anthropology 22:105-131.

Norton-Griffiths, M., D. Herlocker, and L. Pennycuick 1975 The Patterns of Rainfall in the Serengeti Ecosystem, Tanzania. East African Wildlife

Journal 13:347-374. Nowak, R. M., and J. L. Paradiso

Oliver, J. S. 1983

1985

Walker’s Mammals of the World, 4th ed. Baltimore: Johns Hopkins University Press.

Bone Damage Morphologies from Shield Trap Cave, Carbon County, Montana. Ab- stracts, First International Conference on Bone Modification, p. 27.

Pennycuick, C. J. 1971 1979

The Soaring Flight of Vultures. Scientific American 229: 102-109. Energy Costs of Locomotion and the Concept of ‘Foraging Radius.’ In Serengeti: Dynam-

ics of an Ecosystem. A. R. E. Sinclair and M. Norton-Grifiths, eds. Pp. 164-184. Chicago: University of Chicago Press.

Pennycuick, L. 1975 Movements of the Migratory Wildebeest Population in the Serengeti Area between 1960

and 1973. East African Wildlife Journal 13(1):65-87. Portman, 0.

1970

Potts, R. 1982 Lower Pleistocene Site Formation and Hominid Activities at Olduvai Gorge, Tanzania.

1984 Home Bases and Early Hominids. American Scientist 72:336347.

1981 Cutmarks Made by Stone Tools on Bones from Olduvai Gorge, Tanzania. Nature

Nutritional Requirements (NCR) of Non-Human Primates. In Feeding and Nutrition of Nonhuman Primates. R. Harris, ed. Pp. 87-1 16. New York: Academic Press.

Ph.D. dissertation, Harvard University, Cambridge.

Potts, R., and P. Shipman

291~577-580.


Prost, J. H.

Robinson, J. T.

Rodman, P., and H. M. McHenry

thropology 52: 103-106.

1980 Origin of Bipedalism. American Journal of Physical Anthropology 52: 175-189.

1972 Early Hominid Posture and Locomotion. Chicago: University of Chicago Press.

1980 Bioenergetics and the Origin of Hominid Bipedalism. American Journal of Physical An-

Rose, J. J. 1983 A Replication Technique for Scanning Electron Microscopy: Applications for Anthro-

pologists. American Journal of Physical Anthropology 62:255-263. Rose, M. D.

1984 Food Acquisition and the Evolution of Positional Behavior: The Case of Bipedalism. In Food Acquisition and Processing in Primates. D. T. Chivers, B. A. Wood, and A. Bilsborough, eds. Pp. 509-524. New York: Plenum Press.

Rudnai, J. 1973 The Social Life of the Lion. Wallingford, PA: Washington Square East, Publishers.

Savage, R. J. G. 1978 Carnivora. I n Evolution of African Mammals. V. J. Maglio and H. B. S. Cooke, eds. Pp.

249-267. Cambridge, MA: Harvard University Press. Schaller, G.

1968 Hunting Behavior of the Cheetah in the Serengeti National Park, Tanzania. East African

1972 The Serengeti Lion: A Study of Predatory-Prey Relations. Chicago: University ofChicago Wildlife Journal 6:95-100.

Press. Schaller, G., and G. Lowther

1969 The Relevance of Carnivore Behavior to the Study of Early Hominids. Southwest Journal

Senut, B. 1981

of Anthropology 25(4):307-341.

Humeral Outlines in Some Hominoid Primates and in Plio-Pleistocene Hominids. Amer- ican Journal of Physical Anthropology 56:275-283.

Service, E. R.

Shipman, P. 1979 The Hunters. Englewood Cliffs, N.J.: Prentice-Hall.

1981 Applications of Scanning Electron Microscopy to Taphonomic Problems. In The Re- search Potential of Anthropological Museum Collections. Annals of the New York Academy of Sciences 276:357-385.

Early Hominid Lifestyle: Hunting and Gathering or Foraging and Scavenging? In Ani- mals and Archaeology, Vol. 1. J. Clutton-Brock and C. Grigson, eds. Pp. 31-50. London: Brit- ish Archaeological Reports.

1983

1984 Scavenger Hunt. Natural History 93(4):2&27.

1983a Early Hominid Hunting, Butchering and Carcass-processing Behaviors: Approaches to

1983b Evidence of Butchery and Hominid Activity at Torralba and Ambrona: An Evaluation

Shipman, P., and J. J. Rose

the Fossil Record. Journal of Anthropological Archaeology 2( 1):57-98.

Using Microscopic Techniques. Journal of Archaeological Science 10( 3):465-474. Sinclair, A. R. E.

1979 The Serengeti Environment. In Serengeti: Dynamics of an Ecosystem. A. R. E. Sinclair and M. Norton-Griffiths, eds. Pp. 31-45. Chicago: University of Chicago Press.

Stern, J. T., and R. L. Susman 1983 The Locomotor Anatomy of Australopithccus afarensis. American Journal of Physical An-

Steudel, K. thropology 60:279-317.

1980 New Estimates of Early Hominid Body Size. American Journal of Physical Anthropology 52:63-70.

Susman, R. L., and J. T. Stern 1979 Telemetered Electromyography of Flexor Digitorum Profundus and Flexor Digitorum

Superficialis in Pan troglo&es and Implications for Interpretation of the 0. H. 7 Hand. Amer- ican Journal of Physical Anthropology 50:565-574.

1982 Functional Morphology of Homo habilis. Science 2 17:93 1-934.


Szalay, F. 1975

Taylor, C. R. 1977

Hunting-Scavenging Protohominids: A Model for Hominid Origins. Man 10:420-429.

The Energetics of Terrestrial Locomotion and Body Size in Vertebrates. In Scale Effects in Animal Locomotion. T. J. Pedley, ed. Pp. 127-141. London: Academic Press.

Taylor, C. R., N. C. Heglund, and G. M. 0. Maloiy 1982 Energetics and Mechanics of Terrestrial Locomotion, 1: Metabolic Energy Consumption

as a Function of Speed and Body Size in Birds and Mammals. Journal of Experimental Biology 97:l-21.

Tiger, L., and R. Fox

Turnbull, C. 1971

1965a The Mbuti Pygmies of the Congo. I n Peoples of Africa. J. L. Gibbs, ed. Pp. 279-318.

1965b Wayward Servants: The Two Worlds of the African Pygmies. Garden City, NY: Natural

The Imperial Animal. New York: Holt, Rinehart & Winston.

New York: Holt, Rinehart & Winston.

History Press. Van Lawick-Goodall, J., and H. Van Lawick

1970 Innocent Killers. London: Collins. Vrba, E. S.

1979 A New Study of the Scapula ofAustralopithccus ahcanus from Sterkfontein. American Jour- nal of Physical Anthropology 5 1 : 1 17-1 29.

1980 The Significance of Bovid Remains as Indicators of Environment and Predation Patterns. I n Fossils in the Making. A. K. Behrensmeyer and A. P. Hill, eds. Pp. 247-272. Chicago: Uni- versity of Chicago Press.

Walker, A. 1980

1981

1984

Functional Anatomy and Taphonomy. In Fossils in the Making. A. K. Behrensmeyer and

Dietary Hypotheses and Human Evolution. Philosophical Transactions of the Royal So-

Extinction in Human Evolution. In Extinctions. M. Niteki, ed. Pp. 119-152. Chicago:

A. P. Hill, eds. Pp. 182-196. Chicago: University of Chicago Press.

ciety of London (series B) 292:57-64.

University of Chicago Press. Walker, A., and R. E. F. Leakey

Washburn, S. L. 1978 The Hominids of East Turkana. Scientific American 239:54-66.

1960 Tools and Human Evolution. Scientific American 203:63-75. 1978 The Evolution of Man. Scientific American 239:194-208.

1968 The Evolution of Hunting. I n Man the Hunter. R. B. Lee and I. DeVore, eds. Pp. 293- Washburn, S. L., and C. S. Lancaster

303. Chicago: Aldine. Winterhalder, B., and E. A. Smith, eds.

cago: University of Chicago Press. 198 1 Hunter-gatherer Foraging Strategies: Ethnographic and Archaeological Analyses. Chi-

Yellen, J. E. 1977 Cultural Patterning in Faunal Remains: Evidence from the !Kung Bushmen. I n Experi-

mental Archaeology. D. Ingersoll, J. E. Yellen, and W. Macdonald, eds. Pp. 271-331. New York: Columbia University Press.

Zihlman, A. L. 1978 Interpretations of Early Hominid Locomotion. In Early Hominids of Africa. C. J. Jolly,

ed. Pp. 361-377. London: Duckworth. Zihlman, A. L., and L. Brunker

1979 Hominid Bipedalism: Then and Now. Yearbook of Physical Anthropology 22: 132-162.

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