by Brian Fagan
The 1960s through the mid-1980s were
years of epic early hominid discoveries at Olduvai Gorge in Tanzania, at
East Turkana in Kenya, and at Hadar in Ethiopia. These were the years when
human evolution became part of popular culture, when Louis and Mary Leakey,
their son Richard, Donald Johanson, and others became celebrities. It was
Louis Leakey who names the first human Homo habilis, "handy
person" the first toolmaker.
It was he who argued that the scatters of broken bones and crude stone choppers in Bed I at Olduvai were all that was left of temporary encampments hwere e Homo habilis butchered animals, ate, and slept in brush shelters nearly 2 million years ago. Leakey thought that males did the hunting while the women foraged for whild plant foods - an idea based on Canadian anthropologist Richard Lee's work among the !Kung San, a modern hunter- gatherer group living in the Kalahari Desert of southern n Africa. When Richard Leakey discovered more early humans at Koobi Fora a in northern Kenya, this "man the hunter - woman the gatherer " model gained even greater antiquity at least 2. 5 million years.
Although the Leakeys' portrait of Homo habilis was applauded by such eminent archaeologists as the late Glynn Isaac, it rapidly came under fire on the grounds that it was based on imcomplete information However had the scatters of bones and stone fragments been formed? Had they accumulated in a few days. . . even hours? Or were they the result of occasional visits over a long period of time?
The study of what are called "site-formation processes" is relatively new to archaeology. Richard Potts of the Smithsonian Institution has studied the Olduvai "floors" with meticulous care. He used geological evidence to establish that they were, indeed, not of natural origin. Potts examined the ways in which individual bones were fractured, both at their articular ends and along the shafts. He examined the different bones for telltale traces of both carnivore and hominid damage to the same fragments. Potts believes that several agencies were at work in site formation at Olduvai. At least one presumed site was formed predominantly by carnivores; others, which have both artifacts and bones, resulted mostly from hominids bringing tools and bones to the site. Judging from the weathering on individual bones, Potts estimates each "floor" accumulated over a period of about five years. He also believes that they were not campsites at all, but places where hominids cached stone flakes and cores. They used these places regularly when scavenging meat from nearby predator kills.
There are several arguments in favor of Potts's hypothesis. First, the bones and stones are concentrated in tight groupings and were deposited over a considerable period of time. Second, the transported bones bear cut-marks from stone tools. Third, many of the bones were never completely processed and were abandoned while still covered with meat and with marrow intact. Carnivore teeth marks on some of the bones arc occasionally superimposed on stone tool cut-marks, as if hyenas and other animals visited the fresh accumulation after the hominids left. Last, the hominids left lumps of imported but unprocessed stone at the caches, as if they planned to return.
If Potts is right in thinking the Olduvai deposits were indeed stone caches, what about the early human lifeway itself? The animal bones from Olduvai come from a wide variety of species that once flourished near the shallow lake. Did Homo habilis actually hunt antelope and other animals, or did our earliest ancestors merely scavenge meat from lion and hyena kills?
Many experts now believe that Homo habilis scavenged meat from nearby predator kills, chasing away lions with stones and loud calls.. The hominids would then grab choice pieces of meat and retreat to a convenient spot, perhaps under the shade of a tree, where they had already stashed stone flakes and raw materials. There they would eat the fresh meat, using flakes and stones to strip off the flesh and break up the bones for their marrow. Once their hunger was satisfied, they would move off, leaving the smashed bones for other predators to scavenge. The hominids would return to the same place on several occasions, perhaps because there was water nearby, or because a convenient tree provided both shelter and a place of refuge. We can assume, however, that their visits were sufficiently infrequent so that carnivores did not lie in wait for them.
The new research shows that our earliest ancestors behaved in a more ape-like than human manner, spending much of their life in the trees, even if they ventured onto the open savanna for meat and plant foods. They may have run down and hunted a few species of smaller animals, but, as far as we can tell, they hunted without spears. The lack of spears makes close-quarter stalking essential and fleetness of foot vital. It also means that hominids with an upright posture and the ability to run fast were well- equipped to scavenge meat from predator kills, moving in quickly, grabbing convenient body parts, and running away to safety in the shortest possible time. Without fire and spears, our earliest ancestors would have been vulnerable to sudden attack, especially at night. Most likely, then, they slept in trees and did not establish campsites in open country.
This much more ape-like portrait of Homo habilis has been pieced together from a patchwork of telling elues, some of them almost invisible to the naked eye. The new scenario raises a fundamental question about the evolution of human behavior. When did we first hunt big game, live in camps, share food, and become fully "human"?
New research is under way in Ethiopia, so ravaged by civil war and famine in the 1980s. Ethiopian scholars trained at the University of California at Berkeley are collaborating with American scientists on a long-term campaign of survey and excavation. This time they have the benefit of sophisticated satellite images that will enable them to plot the distribution of extensive fossil beds long before a single paleoanthropologist goes into the field a method that is already paving off. Only a few months ago an international team unearthed some hominid teeth at Fejiji in an area where no fossils had ever been found some 600 miles southwest of Hadar where Donald Johanson discovered Lucy more than a decade ago. Johanson and another team have returned to Hadar, and their first season has yielded the remains of 15 hominids between 3 and 3.5 million years old. They include an upper arm bone with such robust shoulder muscle attachments that the individual would have been able to swing with case into the trees.
Perhaps the new finds at Hadar are another indication that our earliest ancestors were more ape-like than human in their behavior; that our humanness is, indeed, relatively recent. As Stephen J. Gould has written, and mitochondrial DNA may show, "We are all products of a recent African twig." Just how recent that twig is is only now becoming apparent. n
Richard Potts's research can be
found in his monograph Early Hominid Activities at Olduvai Gorge (New
York, Aldine de Gruyter 1988).