Humans were apex predators for two million years


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 for Physical Anthropology, Dr. Miki Ben-Dor and Prof. Ran Barkai from the Jacob M. Alkov Department of Archeology at Tel Aviv University, along with Raphael Sirtoli from Portugal, show that humans were an apex predator for about 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 nutrition, until they eventually had no choice but to domesticate both plants and animals, and became farmers.

“Until now, attempts to reconstruct the diet of stone age humans were based primarily on comparisons with hunter-gatherer societies of the 20th century,” explains Dr. Ben-Dor. “This comparison is useless, however, because two million years ago hunter-gatherer societies were able to hunt and consume elephants and other large animals, whereas hunter-gatherers today have no access to such a reward. The entire 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, genetics and physical constitution. Human behavior changes rapidly, but evolution is slow. The body remembers. “

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

“A 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. Producing and maintaining strong acidity requires large amounts of energy, and its existence is evidence for consuming animal products. Strong acidity provides protection against harmful bacteria found in meat, and prehistoric humans, who hunted large animals whose meat was sufficient for days or even weeks, often consumed old meat that contained large amounts of bacteria and therefore needed to maintain a high level of acidity Another indication of being predators is the structure of the fat cells in the bodies of omnivores, fat is stored in a relatively small number of large fat cells, while in predators, including humans, it is the other way around: we have a much larger number of smaller fat cells. The evolution of humans as predators has also been found. adored in our genome. For example, geneticists have concluded that “areas of the human genome were closed to allow a diet rich in t, whereas in chimpanzees, areas of the genome were opened to allow a diet rich in sugar.”

The evidence from human biology was 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 specialized in hunting large and medium-sized high-fat animals. Comparing humans to today’s large social predators, all of whom hunt large animals and obtain more than 70% of their energy from animal sources, reinforced the conclusion that humans specialized in hunting large animals, and indeed , they were hypercarnivores.

“Hunting big game is not an evening hobby,” says Dr. Ben-Dor. “It requires a great deal of knowledge, and lions and hyenas achieve these skills after long years of learning. Clearly, the large animal remains found at countless archaeological sites are the result of the vast experience of humans as animal hunters. Many researchers studying the extinction of large animals agree that hunting by humans played an important role in this extinction, and there is no better evidence of the specialization of humans in hunting large animals. It is likely that, as in today’s predators, hunting itself was a focal human activity for 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 centrality of large animals in the human diet, throughout most of human history. “

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

“The archaeological evidence does not overlook the fact that stone age humans also consumed plants,” adds Dr. Ben-Dor. “But based on the findings of this study, plants only became a major component of the human diet towards the end of the era.”

Evidence of genetic changes and the emergence of unique stone tools for processing plants led researchers to conclude that, beginning about 85,000 years ago in Africa, and about 40,000 years ago in Europe and Asia, there was an increase. gradual consumption of plant foods as well as dietary diversity, according to different ecological conditions. This increase was 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. By contrast, during the two million years that humans were apex predators according to the researchers, long periods of similarity and continuity were observed in stone tools, regardless of local ecological conditions.

“Our study addresses a great deal of current controversy, both scientific and unscientific,” says Professor Barkai. “For many people today, the Paleolithic diet is a critical 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 their ancestors were not vegetarians, and people tend to confuse personal beliefs with scientific reality. Our study is both multidisciplinary and interdisciplinary. We propose a picture unprecedented in its breadth and inclusiveness, clearly showing that humans were initially apex predators, who specialized in hunting As Darwin discovered, the adaptation of species to obtain and digest their food is the main source of evolutionary change, and thus the claim that humans were apex predators for most of their development may provide a broad base for fundamental knowledge about the biological and cultural evolution of humans. ”

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