Hunters or Scavengers?
Studying early hominid behavior is complicated both by poor preservation conditions and by the vast time chasm that separates us from our remotest ancestors.
Two sources of information on very early human behavior survive in East Africa–the first is manufactured artifacts¸ the second scatters of tools and food remains found at a few locations like Koobi Fora in East Turkana¸ northern Kenya¸ and Olduvia.
Concentrations of broken animal bones and stone tools in these regions and a few others have been excavated and studied with meticulous care. The concentrations are usually only some 20 to 30 feet (6 to 9 meters) across places that were visited and used by hominids either places¸ places where they returned to sleep¸ cook food¸ and engage in a wide variety of social activities. Are we¸ then¸ to assume that the Koobi Fora and Olduvai concentrations are evidence that our earliest ancestors also used central places like their successors did? Did they hunt and kill big–game animals¸ or did they merely scavenge flesh from abandoned predators kills?
At Koobi Fora¸ a group found the carcass of hippopotamus in a stream bed about 1.8 million years ago. They gathered around and removed bones and meat from the dead animal with small stone flakes. The sandy deposit in which the artifacts lay so fine that we can be certain that every stone cobble was carried in to make tools at the carcass¸ some of them from as far as 9 miles (14 kilometers) away. The site contains abundant evidence of butchering and of tool manufacture¸ but we do not know if the hominids actually killed the animal.
Site FxJj50¸ is also in an ancient watercourse¸ a place where the hominids could find shade from the blazing sun¸ located close to water and abundant tool–making stone. The site is a cluster of artifacts and fragments¸ including sharp flakes¸ choppers¸ and scrapping tools. More than 2000 bones from at least 17 mammalian species¸ mostly antelope¸ are associated with the tools¸ some of which have been chewed by hyenas and other carnivores. There are clear signs the bones were smashed and cut by hominids¸ for reconstructed fragments show traces of hammer blows and finer grooves that may have resulted only from cutting bones with stone flakes. Many of the FxJj50 bones have their articular ends chewed off by carnivores¸ a characteristic of bone accumulations resulting from carnivore kills. Perhaps the hominids simply chased away lions and other predators¸ then moved in on a fresh kill; we cannot be sure.
At Olduvia Gorge¸ Mark Leakey plotted artifact and bone scatters in the lowest levels of the ancient lake beds. Many artifacts and bones were concentrated in areas about 15 feet across (4.6 meters)across. At one site a pile of shattered bones and rocks lay a short distance away¸ the bones perhaps piled in heaps as the marrow was extracted from them. Recent microscopic studies of the Olduvai shattered bones that many of the bones were heavily weathered. They had lain on the surface for considerable periods of time¸ some for perhaps as long as a decade. The bones of many different animals come from the scatters¸ parts of carcasses from a very ecologically diverse set of animals. Limb bones predominate¸ as if these body parts were repeatedly carried to the sites.
At both Koobi Fora and Olduvai¸ meat– and marrow–rich bones occur concentrated in small areas with stone tools. The percentage of carnivore bones is somewhat higher than in the natural environment¸ as if there was intense competition between hominids and other carnivores. Perhaps the presence of such predators restricted the activities of hominids at Olduvai. They may have grabbed meat from fresh carnivore kills and then taken booty to a place where they had a collection of stone tools near water or other predictable food supplies. There they would hastily cut off met extract the marrow before abandoning the fresh bones to the carnivores hovering nearby. Without fire or domesticated animals¸ scientists believe that Homo habilis probably had to rely on opportunistic foraging for game meat¸ it being unsafe for them to camp in open watercourses or on lake shores. It is worth noting that one hominid bone found at Olduvai Gorge had been gnawed by carnivore.
Most of the bones from the Olduvai accumlations are of smaller animals that could be run down and thrown to the ground with ease. This is more of an apelike form of behavior¸ although apes have been observed scavenging meat. Microscpoic studies of the Olduvai bones show that the hominids rarely butchered and disarticulated large animals and carried their bones back to base. They seem to have dismembered predator kills. In some cases¸ human cutting marks overlay predator tooth marks¸ as if the hominids had scavenged bones from carcasses that had already been killed by other animals. In other¸predators have chewed bones abandoned by Homo.
Archaeologist Robert Blumenschine has spent several field season studying animal predators on the game–rich Serengeti Plains of northern Tanzania. Semi–arid grassland crossed by occasional streams lined with trees¸ this was the kind of environment that early hominids shared with other predators like lions and hyeanas. Blumenschine observed dozens of predator kills¸ studying the abandoned¸ shattered bones and comparing then to the archaeological finds at Olduvai Gorge. As a result of these observations¸ he beleives the hominids could take unquie advantage of two scavenging opportunities. The first was near streams¸ because lions kill close to water in the dry season. Sometimes more than a day would elapse before hyenas moved in¸ ample time¸ Blumenschine beleives¸ for hominids to seize their share. It is here¸ too¸ that leopards hide small antelope kills in trees¸ high above the ground¸ but not out of reach of humans. Scavenging would have been most common in the dry months¸ when game (and its predators) stayed near to premanent water supplies and plant foods were in short supply. During the rains¸ both antelope and predators would range far over the plains¸ where it was easy for hyenas to find lion kills. However¸ these were the months when hominids relied on plant foods and fruit in more wooden environments. Blumenschine argues that scavenging and plants gathering went hand–in–hand¸ however¸ plants and all kinds of vegetable foods were an important¸ if not the most important¸ part of very early human diet.
