Ramapithecines were the earliest ancestors of humans (www.ivu.org/history/early/ancestors.html
). They lived in subtropical forests that did not provide a year-round supply of food, so consequently they were forced to forage for plant life on the ground. It is also thought that they were vegetarians because of the abundance of wild grasses and cereals during that time period (about eight million years ago). The Austrapithecines, known as the Southern apes, succeeded the Ramapithecines about five million years ago. These were primates that, along with showing bipedalism (walking upright on two feet, a characteristic first seen in Ramapithecines), also developed the hunter-gatherer way of life ("a member of a culture in which food is obtained by hunting, fishing, and foraging rather than by agriculture or animal husbandry" (http://www.webster.com/cgi-bin/dictionary
)). The Austrapithecines used tools, but their skull was not quite humanlike yet (it was smaller, like an ape skull). It has been suggested that Austrapithecines, "developed bipedalism in order to reach fruits growing on small trees" (www.ivu.org/history/early/ancestors.html
The next three primate descendants were Homo habilis, (1.6 million years ago), Homo erectus (half a million years ago), and Neanderthal Man (130,000 years ago). Scientists found that these three ancestors evolved into partial meat-eaters. These primate descendants ate a small range of lean meats, beginning by scavenging dead animals that had been previously killed and partially eaten by other creatures. There was a skeleton found from the Homo erectus era that had symptoms of hypervitaminosis (or an excess of Vitamin A), which is most likely caused by eating meat (www.ivu.org/history/early/ancestors.html
). It is also thought that Homo habilis was the first omnivorous group of humans because "there is evidence of cut-marks on animal bones, as well as use of hammer stones to smash them for the marrow inside" ("Home Bases and early homonids," 1984). Forty thousand years ago Homo sapiens, modern humans, evolved. These modern hunter-gatherers have very similar eating patterns that resemble those of preagricultural human beings.
There has been evidence of the biological similarities between humans and chimpanzees. The DNA difference between gorillas, chimpanzees, and humans is less than one percent, less than between different species of horse (www.veg.ca/newsletr/novdec96/evolution.html
). Dr. Katherine Milton, professor of anthropology at the University of California, has been studying these similarities. She discovered that the complexities of the food niche could have been a factor in increasing the longevity of primates, and that Homo sapiens were better equipped to solve dietary problems from changing environmental conditions. She also has found that dental patterns among fossils of early humans supports evidence of a high quality, plant-based diet, closely related to the ninety-four percent plant and fruit diet of chimpanzees. Finally, Milton’s studies have shown that the chimpanzee’s stomach is extremely similar to the efficiency of the human’s stomach to process fiber. "According to Milton, our digestive tract does not seem to be greatly modified from that of the common ancestor of apes and humans, which was undoubtedly a predominantly herbivorous animal" (www.veg.ca/newsletr.novdec96/evolution.html
According to Dr. David Ryde, early humans are even more closely related socially and nutritionally to the Bonobo chimpanzee. Bonobo chimps have a high percentage of fruit in their diet (about eighty percent) and also consume fewer insects than the average ape. Bonobo chimps are not only similar to humans in their nutrition, but they are very similar in their sexual relationships. For example, when "arguments" occur between bonobos, sexual engagement afterwards may serve as a way to smooth the incident over and to re-establish normal relations again. These social similarities suggest that our ancestors and chimpanzees’ ancestors are similar, almost identical (http://www.beyondveg.com/nicholson-w...erview1c.shtml
Paleolithic humans had some tools to hunt with, but they were not as useful as tools used by the modern hunter-gatherer. Professor Jared Diamond explains how the diet of early humans depended on their tools. He describes how he was invited on a hunt by a tribe in New Guinea that retained Stone Age "technology" and habits. Surprisingly, after an entire day of hunting, the tribe returned with only two baby birds, a few frogs, and mushrooms.
Although the men of the tribe frequently boasted of the large animals they had killed, when pressed for details, they admitted that large animals were killed only a few times in a hunter’s career. These peoples’ stone tools were far more advanced than the stone tools found on prehistoric sites, so Professor Diamond thinks it unlikely that prehistoric hunters could have enjoyed a much higher success rate than present day hunter-gatherer tribes (www.ivu.org/history/early/ancestors.html
This suggests that since a modern hunter-gathering group was not very successful, then it was highly unlikely for our ancestors to be able catch even one large prey with their limited equipment. Like the New Guinea tribe, groups such as the Kalahari bushman and the Australian aborigines gather much of their food in the form of roots, fruit, nuts and other nutritious plant products. The proportions by weight of vegetable food and animal food in their diet compared with modern humans are about 81.3% vegetable and 18.7% animal (www.ivu.org/history/early/ancestors.html
The energy and caloric intake requirements of preagricultural humans compared to modern humans vary considerably. Paleolithic humans were lean, robust, and needed a higher caloric intake than present humans. Researchers explain, "Fruits, roots, legumes, nuts and other noncereals provided sixty-five to seventy-five percent of the average forager substance…which were generally consumed within hours of being gathered" (Eaton, Eaton III, Konner, 1992). These foods were often eaten uncooked; therefore, they still contained a high amount of vitamins and minerals. For some nutrients, the intake required for Paleolithic humans would have now only been received through vitamin supplements, such as folic acid.
In conclusion, there has been an extensive amount of research done on the topic of Paleolithic vegetarians. There also have been various theories about our early ancestors such as theories that the habitat of subtropical forests determined vegetarianism-like diet. Skeletal remains support this contention in both the Austrapithecines and the Austrapithecine Ramidus. Evidence suggests humans became carnivorous only within the Homo habilis, Homo erectus, and Neanderthal Man stages of evolution. Research also suggests that early humans’ diets are similar to those of the chimpanzee, which subsisted on a mostly plant-based diet. Anthropologists who study human tribes with Stone Age Technology and habits reveal that these humans eat mostly plants and small animals, and only rarely eat large prey. Finally, studies on Paleolithic humans suggest they existed on a moderately low protein and high fiber diet, furthering the argument that prehistoric humans were probably more herbivorous than carnivorous, though certainly this debate requires further research.