Darwin's conception of early prehistoric humans as confident, clever hunter-gatherers has long dominated anthropology. His theory has been reinforced by an accident of history: the human fossil record has been found largely in reverse order. Remains of humans' most recent forebears, who lived 35,000 to 100,000 years ago, were discovered in 1856; over the next century, discoveries yielded fossils of hominids from progressively earlier eras. Because the first-discovered fossil hominids, the Neanderthals, genuinely resembled modern humans, anthropologists from Darwin on have confused the life-styles of today's nonindustrial peoples with those of our distant hominid forebears. These anthropologists have failed to consider both the sophistication of modern hunter-gatherer societies (including their use of fire, clothing, shelter, weapons, tools, language, and complex strategies) and the ways in which their environments differ from prehistoric ones (for example, in containing fewer large animal predators).

Recent intellectual developments, such as the new field of taphonomy, have called into question the traditional hypothesis that early hominids outsmarted the predators with whom they competed for meat and that they mastered their world through hunting. Taphonomy investigates the transformation of skeletal remains into fossils—it asks, for example, whether bone piles have been deposited by predators, hunters, or floodwaters, and whether hyenas' teeth scar animal bones differently than do human tools.

Taphonomy has been utilized by some researchers in studying a group of animal fossils, hominid fossils, and stone tools that were almost two million years old. By comparing the microscopic features of linear grooves on the fossilized animal bones with similar grooves on modern bones, the researchers found that cut marks made by stone tools differed from the marks of other taphonomic agents, such as carnivores' teeth or sedimentary abrasion. They also found that the markings of stone tools on many of the fossilized animal bones did not occur systematically at the joints and that toothmarks of animal carnivores often underlay rather than overlay the cut marks.

The researchers hypothesized from this evidence that early hominids were scavengers of meat left from carnivore kills, rather than hunters of live prey. From patterns of wear on fossilized hominid teeth, the researchers further deduced that early hominids, like other scavengers, ate fruit primarily and meat only occasionally. Early hominids could have been well adapted for scavenging: agility in climbing trees helped them escape predators and gain superior vantage points, and an upright mode of walking enabled them to scan the ground for carcasses and to carry useful scavenging tools. According to these researchers, Darwin's vision of early prehistoric hunters may be familiar and appealing, but the fossil record suggests a revised picture of less-confident early hominids who often perched in trees and who foraged and scavenged alone or in small groups.