Humans were predators for two million years – our Stone Age ancestors mostly ate meat

Researchers at Tel Aviv University were able to reconstruct the diet of people from the Stone Age.

In an article published in the Yearbook of the American Physical Anthropology Association, dr. Miki Ben-Dor and prof. Ran Barkai of the Jacob M. Alkov Department of Archeology at Tel Aviv University, along with Raphael Sirtoli of Portugal, that humans have been a top predator for about two million years. Only the extinction of larger animals (megafauna) in different parts of the world, and the decline of animal food resources by the end of the Stone Age, led people to gradually increase the vegetable element in their diet, until they finally had no other choice. had as housing both plants and animals – and became farmers.

“So far, the attempts to reconstruct the diet of people from the Stone Age have mostly been based on comparisons with 20th-century hunter-gatherer associations,” explains Dr. Ben-Dor. ‘However, this comparison is useless, because two million years ago hunter-gatherers could hunt and devour elephants and other large animals – while today’s hunter-gatherers do not have access to such abundance. The whole ecosystem has changed and the conditions can not be compared. We decided to use other methods to reconstruct the diet of people from the Stone Age: to examine the memory stored in our own bodies, our metabolism, genetics and physical build-up. Human behavior changes rapidly, but evolution is slow. The body remembers. ”

In an unprecedented process, dr. Ben-Dor and his colleagues collected about 25 lines of evidence from about 400 scientific articles from different scientific disciplines, dealing with the focus question: Were people from the Stone Age carnivores, or were they generalist omnivores? ? Most evidence has been found in research on current biology, namely genetics, metabolism, physiology and morphology.

“One prominent example is the acidity of the human stomach,” says Dr. Ben-Dor. ‘The acidity in our stomach is high compared to omnivores and even other predators. The production and maintenance of strong acidity requires large amounts of energy, and its existence is proof of the consumption of animal products. Strong acidity provides protection against harmful bacteria found in meat, and prehistoric people who hunt large animals whose meat was sufficient for days or even weeks, often contain old meat that contains large amounts of bacteria and was therefore needed to maintain a high acidity. maintain. ”

Another indication of predators is the structure of the fat cells in our bodies. In the bodies of omnivores, fat is stored in a relatively small number of large fat cells, while in predators, including humans, the opposite is true: we have a much larger number of smaller fat cells. Important evidence for the evolution of humans as predators was also found in our genome. Geneticists, for example, concluded that “regions of the human genome have been closed off to allow a high-fat diet, while the regions of the genome have been opened up in chimpanzees to allow a high-sugar diet.”

Evidence from human biology has been supplemented by archaeological evidence. Research on stable isotopes in the bones of prehistoric humans, as well as hunting practices peculiar to humans, shows, for example, that humans specialized in hunting large and medium-sized animals with a high fat content. Comparing humans to today’s large social predators, all of which hunt large animals and derive more than 70% of their energy from animal sources, reinforces the conclusion that humans specialize in hunting large animals and are in fact hypercarnivorous.

“Hunting large animals is not an afternoon hobby,” says Dr. Ben-Dor. ‘It takes a lot of knowledge, and lions and hyenas achieve these abilities after many years of learning. It is clear that the remains of large animals found in countless archaeological sites are the result of man’s great expertise as hunters of large animals. Many researchers studying the extinction of large animals agree that hunting by humans has played an important role in this extinction – and there is no better evidence of human specialization in hunting large animals. Most likely, as in modern-day predators, hunting itself was an important human activity during most of human evolution. Other archaeological evidence – such as the fact that specialized tools for obtaining and processing vegetable foods only appeared in the later stages of human evolution, also supports the centrality of large animals in the human diet throughout most of human history. ‘

The multidisciplinary reconstruction that TAU ​​researchers have been doing for almost a decade proposes a complete change of paradigm in the understanding of human evolution. Contrary to the common hypothesis that humans owe their evolution and survival to their flexibility in diet, which enabled them to combine the hunting of animals with plant foods, the picture that emerges here is that humans mostly developed as predators of large animals.

“Archaeological evidence does not rule out the fact that people from the Stone Age also consumed plants,” adds Dr Ben-Dor. “But according to the findings of this study, plants only became an important component of the human diet by the end of the era.”

Evidence of genetic changes and the emergence of unique stone tools for processing plants have led researchers to conclude that there was an increase in the consumption of vegetable crops about 85,000 years ago in Africa and about 40,000 years ago in Europe and Asia. food took place. as well as dietary variety – in accordance with varying ecological conditions. This increase was accompanied by an increase in the local uniqueness of the stone tool culture, which is similar to the diversity of material cultures in the 20th century hunter-gatherers’ associations. In contrast, during the two million years when humans were toppers, according to the researchers, long periods of similarity and continuity were observed in stone tools, regardless of local ecological conditions.

“Our study addresses a very large current controversy – scientific as well as non-scientific,” says prof. Barkai. “For many people today, the Paleolithic diet is a critical issue, not only in the past, but also in the present and in the future. It is difficult to convince a pious vegetarian that his / her ancestors were not vegetarians, and that people tend to confuse personal beliefs with scientific reality. Our study is multidisciplinary and interdisciplinary. We present a picture that is unprecedented in its inclusivity and breadth, which clearly shows that humans were initially top predators that specialized in hunting large animals. As Darwin discovered, adapting species to obtain and digest their food is the main source of evolutionary change, and so the claim that humans were predators for most of their evolution may provide a broad basis for fundamental insights. on biological and cultural evolution. of people. ”

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