How Did Early Hominids Find Food During The Old Stone Age?

The Paleolithic Era, or Old Stone Age, marked the first and longest period of human history. Beginning 4 million years ago and continuing to 10,000 B.C., it saw early hominids living as foragers, consuming whatever food sources were available. Scientists once believed these early human ancestors were mostly vegetarians, eating meat only very rarely. New research, however, complicates that. Although the earliest hominids were primarily herbivores, later groups turned more to fish and animal proteins. This alteration in diet went along with certain evolutionary changes, leading to the rise of modern humans.

The few existing dental remains reveal that the earliest hominids lived by gathering nuts, berries and other wild vegetation. Without tools, they were only able to consume meat by scavenging eggs or picking carcasses left by predators. Their body structure was that of an herbivore's as well. A more prominent mandible with sizable grinding molars, such as those of Australopithecus anamensis, made it easier to break down plant fibers. A larger digestive tract with specialized enzymes aided their digestion. Yet, gradually, as primitive tool-making advanced, meat consumption rose dramatically.

By 1.5 million years ago, Homo erectus had developed tools for hunting and butchering animals. Scientists believe it was then that meat overtook plant sources in the hominid diet. By the late Paleolithic Era, roughly 65 percent of all food intake came from animals. Various sites in China reveal that Peking Man exploited deer, pigs, buffalo, sheep and even rhinoceroses. Butchering marks have also been found on animal bones across Europe. In a very rare find, archaeologists in the 1950s discovered a red deer skeleton with a Neanderthal spear still intact.

Through chemical analysis, scientists have determined that European Neanderthals dined on large quantities of freshwater fish. In certain Atlantic coastal regions, fish appears to have been the primary source of protein. While early Neanderthals fished with crude spears, the modern humans who replaced them 40,000 years ago crafted hooks out of small animal bones. But by this point, hominid groups were also consuming shellfish. This has been determined by archeological finds in Kenya, China and elsewhere.

There is now considerable evidence suggesting that meat consumption went hand-in-hand with human evolution. For instance, the large digestive tract of early hominids gradually shrank to better process animal proteins. Over time, the size of the human jaw decreased, since prolonged chewing was no longer necessary. The most significant adaptation, however, was in brain size. As the brain grew larger, it required more energy, thus forcing conversion to a meat-based diet. It was this new brain that distinguished modern humans, enabling them to refine their tool-making, establish agriculture, domesticate animals and bring the Neolithic Era into being.