Humans have been apex predators for two million years – our Stone Age ancestors ate mostly meat

Researchers at Tel Aviv University were able to reconstruct the nutrition of Stone Age humans.

In an article published in the Yearbook of the American Association of Physical Anthropology, Dr Miki Ben-Dor and Professor Ran Barkai of the Jacob M. Alkov Department of Archeology of Tel Aviv University, with Raphael Sirtoli of Portugal, show that humans have been a top predator for around two million years. Only the extinction of larger animals (megafauna) in various parts of the world, and the decline of animal food sources towards the end of the Stone Age, led humans to gradually increase the plant element in their diet. , until they finally had no choice but to domesticate plants and animals – and became farmers.

“Until now, attempts to reconstruct the diet of Stone Age humans have been based primarily on comparisons with 20th century hunter-gatherer societies,” says Dr. Ben-Dor. “This comparison is futile, however, because two million years ago hunter-gatherer societies could hunt and consume elephants and other large animals – whereas today’s hunter-gatherers did not. no access to such a bonus. The whole ecosystem has changed and conditions cannot be compared. We decided to use other methods to reconstruct the diet of Stone Age humans: examining the memory preserved in our own bodies, our metabolism, our genetics and our physical makeup. Human behavior changes rapidly, but evolution is slow. The body remembers.

In a process unprecedented in its magnitude, Dr Ben-Dor and his colleagues collected around 25 sources of evidence from around 400 scientific papers from different scientific disciplines, addressing the central question: humans in the Stone Age were they specialized carnivores or were they generalist omnivores? ? Most of the evidence has been found in research on current biology, namely genetics, metabolism, physiology and morphology.

“A striking example is the acidity of the human stomach,” says Dr. Ben-Dor. “Our stomach’s acidity is high compared to omnivores and even other predators. The production and maintenance of high acidity requires large amounts of energy, and its existence is evidence of the consumption of animal products. High acidity provides protection against harmful bacteria found in meat and prehistoric humans, chasing large animals that had enough meat for days or even weeks, often consumed old meat with large amounts of bacteria, and therefore necessary to maintain a high acidity level.

Another indication of being predators is the structure of the fat cells in our body. In the body of omnivores, fat is stored in a relatively small number of large fat cells, while in predators, including humans, the reverse is true: we have a much larger number of smaller fat cells. . Significant evidence for the evolution of humans as predators has also been found in our genome. For example, geneticists have concluded that “areas of the human genome have been closed to allow a high fat diet, while in chimpanzees areas of the genome have been opened to allow a high sugar diet.”

Evidence from human biology has been supplemented by archaeological evidence. For example, research on stable isotopes in the bones of prehistoric humans, as well as hunting practices unique to humans, shows that humans have specialized in hunting large and medium-sized animals with high fat content. Comparing humans to today’s large social predators, which hunt all large animals and get more than 70% of their energy from animal sources, reinforced the conclusion that humans specialize in hunting large animals and were in fact hypercarnivores.

“Hunting large animals is not an afternoon pastime,” says Dr. Ben-Dor. “It takes a lot of knowledge, and lions and hyenas achieve these abilities after years of learning. Obviously, the remains of large animals found in countless archaeological sites are the result of humans’ great expertise as hunters of large animals. Many researchers who study the extinction of large animals agree that hunting by humans played a major role in this extinction – and there is no better evidence for the specialization of humans in hunting. large animals. Most likely, as with modern predators, hunting itself was a focal human activity throughout most of human evolution. Other archaeological evidence – such as the fact that specialized tools for obtaining and processing plant foods only appeared in the later stages of human evolution – also supports the central role of large animals in human nutrition, throughout. throughout most of human history.

The multidisciplinary reconstruction carried out by TAU researchers for nearly a decade offers a complete paradigm shift in the understanding of human evolution. Contrary to the popular assumption that humans owe their evolution and survival to their dietary flexibility, which has allowed them to combine animal hunting with plant foods, the picture that emerges here is that of humans evolving primarily by as predators of large animals.

“Archaeological evidence does not overlook the fact that Stone Age humans also consumed plants,” adds Dr. Ben-Dor. “But according to the results of this study, plants did not become a major component of human nutrition until towards the end of the era.”

Evidence for genetic changes and the appearance of unique stone tools for processing factories led researchers to conclude that, starting around 85,000 years ago in Africa and around 40,000 years ago in Europe and Asia, a gradual increase consumption of plant foods has occurred. as well as dietary diversity – depending on varying ecological conditions. This rise has been accompanied by an increase in the local uniqueness of stone tool culture, which is similar to the diversity of material cultures in 20th century hunter-gatherer societies. In contrast, during the two million years that the researchers believed humans were top predators, long periods of similarity and continuity were observed in stone tools, regardless of local ecological conditions.

“Our study addresses a very big current controversy – both scientific and non-scientific,” says Professor Barkai. “For many people today, the Paleolithic diet is a crucial issue, not only with regard to the past, but also with regard to the present and the future. It is difficult to convince a devout vegetarian that his ancestors were not vegetarians, and people tend to confuse personal beliefs with scientific reality. Our study is both multidisciplinary and interdisciplinary. We offer an image unprecedented in its inclusiveness and breadth, which clearly shows that humans started out as top-notch predators, specializing in hunting large animals. As Darwin discovered, the adaptation of species to obtaining and digesting their food is the primary source of evolutionary change, and thus the claim that humans were major predators for most of their life. development can provide a broad basis for fundamental information on biological and cultural evolution. humans. “

Reference: “The evolution of the human trophic level in the Pleistocene” by Miki Ben-Dor, Raphael Sirtoli and Ran Barkai, March 5, 2021, American Journal of Physical Anthropology.
DOI: 10.1002 / ajpa.24247