The Earliest Tool Users and Toolmakers and Early Hominin Behavior

Recognizable stone tools first appear in the archaeological record around 2.5 Ma in east Africa; they are associated with two hominin groups, Paranthropus and early Homo (see Susman, 1988; Schick & Toth, 1993; Kimbel et al., 1997; Deacon & Deacon, 1999; Pickering, 2001) (Figure 4.8). These early stone tools are referred to as the "Oldowan industry" because they were first recognized from localities within Olduvai Gorge. So far the earliest stone tools are those found at the Gona and Bouri sites, Hadar, Ethiopia, dating to around 2.5 Ma; from Lokalelei, West Turkana, Kenya, dating to around 2.4 Ma; from Koobi Fora dated to around 1.9 Ma; and from Olduvai Gorge, dating to around 1.8 Ma (M.D. Leakey, 1971, 1994; Potts, 1988, 1996; Isaac & Isaac, 1997; Kimbel et al., 1997; Semaw et al., 1997; Heinzelin et al., 1999).

The earliest tools from Gona comprise simple cores, whole flakes, and flaking debris. There is evidence of ongoing flake scars on the cores, indicating that the early hominins (H. habilis?) had mastered the skills of basic stone knapping (Semaw et al., 1997; Kimbel et al., 1997). Indeed, Semaw et al. (1997) argue that the material they recovered from the Gona localities show surprisingly sophisticated control of stone fracture mechanics, which they suggest is equivalent to much younger Oldowan assemblages of around 1.8 Ma.

The nearby stone tool localities around Bouri, which also date to around 2.5 Ma, are said to be associated with the "Australopithecus" garhi (Heinzelin et al., 1999), though the fossil hominid remains were not found at the same locality as the tools. It is also from this region that we have early Homo dating to 2.3 Ma (Kimbel et al., 1997), and it cannot be dismissed that these tools are from the hand of Homo. Mammal remains from this time zone have also been discovered with cut marks and percussion marks said to be made by stone tools. Further, Heinzelin et al. (1999)

Bifacial chopper Hammer stone

Bifacial chopper Hammer stone

0 5 cm Heavy-duty (core) scraper

Figure 4.8 ► Two types of typical Oldowan tools from Koobi Fora. Top is a classic bifacial chopper; bottom is a more specialized heavy-duty tool (core scaper). From Schick and Toth (1993), p. 113.

0 5 cm Heavy-duty (core) scraper

Figure 4.8 ► Two types of typical Oldowan tools from Koobi Fora. Top is a classic bifacial chopper; bottom is a more specialized heavy-duty tool (core scaper). From Schick and Toth (1993), p. 113.

suggest that the bone modifications indicate that large mammals were disarticulated and defleshed, and that their long bones were broken open and the marrow extracted. The raw material for tool manufacture was not local and had to be transported into the area, as happened much later at Olduvai (see Potts, 1988). Heinzelin et al. (1999) conclude that the major function of the earliest known tools was meat and marrow processing of large carcasses.

It is clear that by around 2.5 Ma a distinct behavioral shift had occurred in food acquisition and processing. Oldowan toolmakers were beginning to unlock the vast amount of nutrition stored up in large mammals' carcasses. It is with the first appearance of the genus Homo that we see evidence of vastly increased stone tool distribution throughout the landscape, associated with large mammal remains, which provide evidence of butchering. All evidence suggests that this behavioral shift can be associated with the emergence of Homo, as opposed to Paranthropus, whose diet was more specialized, focusing on tough, gritty foods that have left many scratch marks and pits on their grinding, stonelike molar teeth (Kay & Grine, 1988). While some tool use may have occurred in Paranthropus, Homo was the first to shift dramatically to a dependence on this new technology. So, while Paranthropus appears to have used its grindstone-like molars to process its hard, gritty foods, early Homo shifted to a stone tool technology, not only to help in food processing, but perhaps also to help in its acquisition.

Is there any additional archaeological evidence to support the Central Place Foraging model (Isaac, 1976, 1978, 1989), the Scavenging hypothesis (Binford, 1981), or the Stone Tool Caching model (Potts, 1988) for later Pliocene early or Pleistocene Homo? The site of FLK North-6, located within the main gorge at Olduvai, in the upper part of Bed I, dated to around 1.7 Ma, has been interpreted as an early hominid butchering site (M.D. Leakey, 1971). The excavations in trenches IV and V revealed the remains of an almost complete elephant skeleton, which has been described by M.D. Leakey, where an elephant was cut up by early man, who may have come across it accidentally, or deliberately driven it into a swamp to be slaughtered. The tools found nearby would seem to represent those used for cutting the meat off the carcass (1971:64).

Based solely on the association of numerous stone tools and elephant remains, Leakey argued that they are contemporary and concluded that they are part of a prehistoric residue of activity. While M.D. Leakey (1971) discusses bone modification on mammalian remains, no mention was made of human-induced modifications to the elephant remains. Thus the "butchery" site is based purely on the association of tools and elephant remains, which must be viewed with some caution.

This type of associative analysis of early hominin behavior can also be seen in Binford's (1981) "residual" analysis of early hominin debris from Olduvai. Binford concentrated on distinguishing between carnivore and hominin behavioral debris patterns. In his approach, any archaeological pattern that cannot be attributed to carnivores (as defined by extant carnivore residual patterns) is assigned to hominin activity. The major problem with this approach is the factoring out of "carnivore debris patterns." It does not allow for any overlap between the multiple use of animal carcasses by both carnivores and hominids (Cameron, 1993b). Also, because Binford could explain such patterns using only extant carnivores, he failed to appreciate possible extinct and other extant carnivore patterns that may have contributed to the archaeological bone accumulation. For example, what about the felids Dinofelis and Megantereon and the hyaenid Euryboas (Groves, 1989a)? In his multivariate analysis of the assemblage composition present at

FLK North-6, Binford argued that the site, like FLKNN-2, represents a carnivore den assemblage. This is based on the similarity of Q-mode factor loadings between these sites and those of modern carnivore den assemblages.

Potts (1988) questioned Binford's carnivore versus hominin bone pattern assemblage analysis. He argued that the large degree of variability between contemporary carnivore debris patterns (not to mention extinct patterns) would make it very difficult to identify the phenomenon responsible for the debris observed in the archaeological record. He stated (p. 135) that our current knowledge of carnivore bone accumulations and damage includes significant variation in the species observed (e.g., spotted hyenas versus wolves) and in observation conditions (e.g., bones fed to zoo animals versus bones recovered from natural dens and kill sites). Even within species, bone damage and selection of parts for transport may vary with environmental factors. Although there may be features in common to carnivore bone accumulations, it is still unclear how well these features distinguish carnivore collections from bones collected and modified by hunter-gatherers.

Potts (1986, 1988), Potts and Shipman (1981), Bunn (1981, 2002), and Bunn and Kroll (1986) all conducted microscopic analyses of fossilized bone from Olduvai and all were able to identify stone tool cut marks as well as carnivore tooth marks on bone fragments. These analyses have refuted Binford's claim that FLK North-6 is solely representative of a prehistoric carnivore den. Potts's analysis has clearly shown that hominins and other carnivore species were involved in utilizing the remains at Olduvai.

Binford (1981, 1985, 1988) also argued against Isaac's Central Place Foraging hypothesis, which is the model we think is the most likely behavioral repertoire for early Homo. (See previous chapter.) Binford believed that early Homo was scavenging the leftovers of other carnivores and so had access only to low-food-utility items that carnivores chose not to eat, and had to scavenge these items quickly before moving off to a more protected area away from the kill site. Most Olduvai archaeological sites, he contended, if they can be attributed to hominin activities at all, represent optimal scavenging activities. Potts (1986) refuted Binford's argument and established that the bone formations had accumulated over a 5- to 10-year period or even more. This is an important point, which indicates that some form of central place foraging was indeed being used by the early hominins. It is clear that during this period, hominins contributed to these concentrated scatters, because tool cut marks can be identified on many pieces of bone that accumulated over long periods. Specific locations were being used by early Homo over a period of years, which indicates to us that, again, Isaac's Central Place Foraging model is the most likely explanation (Cameron, 1993a; Cameron & Groves, 1993). The processes and likely reasons for this dietary and behavioral shift will be examined in later chapters.

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