Food for Thought; February 2006; Scientific American Magazine; by Kate Wong; 3 Page(s)

For the first million years of their existence, the early members of our genus, Homo, shared the African landscape with another group of hominids, the robust australopithecines. Although the two groups were closely related, there were striking differences between them. Perhaps most notably, the robusts had giant molars, thick tooth enamel and a bony crest atop the skull that anchored huge chewing muscles. Paleoanthropologists have long believed that the robusts used their elaborate headgear to process tough plant foods. But the results of a new study suggest otherwise.

Received ecological wisdom holds that two closely related species cannot live side by side unless they differ significantly in the way they use local resources. To explain how early Homo coexisted with the robusts for so long--and under the difficult circumstances of a global drying trend that replaced food-rich forests with grasslands--experts concluded that whereas Homo developed a large brain and tool-making capabilities that enabled it to pursue a diet rich in meat, the robust australopithecines became dedicated vegetarians, evolving the anatomical equivalent of a Cuisinart to grind up nuts, fruits, seeds or tubers, or some combination thereof.