Ancient humans were top predators for 2 million years, study finds: ScienceAlert

Paleolithic cuisine was anything but lean and green, according to a study of the diets of our Pleistocene ancestors.

For a good 2 million years, Homo sapiens and their ancestors gave up salad and ate a lot of meat, putting them at the top of the food chain.

It’s not quite the balanced diet of berries, grains, and steak that we might imagine when we think of “paleo” food.

But according to a study last year by anthropologists from Tel Aviv University in Israel and the University of Minho in Portugal, modern hunter-gatherers have given us the wrong impression of what we once ate.

“This comparison is futile, however, because 2 million years ago hunter-gatherer societies could hunt and consume elephants and other large animals – whereas today’s hunter-gatherers do not. don’t have access to such a bonus,” said researcher Miki Ben-Dor of Israel’s Tel Aviv University. explained in 2021.

A look at hundreds of previous studies — on everything from modern human anatomy and physiology to measurements of isotopes inside ancient human bones and teeth — suggests we were primarily apex predators until now. to about 12,000 years ago.

Piecing together the grocery list of hominids who lived 2.5 million years ago is made even more difficult by the fact that plant remains don’t preserve as easily as bones, teeth and shells. animals.

Other studies have used chemical analysis of bones and tooth enamel to find localized examples of diets high in plant matter. But extrapolating this to humanity as a whole is not so straightforward.

We can find plenty of evidence of game hunting in the fossil record, but to determine what we have collected, anthropologists have traditionally turned to modern ethnography on the assumption that little has changed.

According to Ben-Dor and his colleagues, this is a huge mistake.

“The whole ecosystem has changed and the conditions cannot be compared,” Ben-Dor said.

The Pleistocene Epoch was a defining period in Earth’s history for us humans. In the end, we were walking to the farthest corners of the globe, outliving all the other hominids on our branch of the family tree.

Chart showing where Homo sapiens sitting on the carnivorous to herbivorous spectrum during the Pleistocene and Late Pleistocene (UP). (Dr Miki Ben Dor)

Dominated by the last great ice age, most of what is now Europe and North America was regularly buried under thick glaciers.

With so much water locked up as ice, ecosystems around the world were very different from what we see today. Great beasts roamed the landscape, including mammoths, mastodons and giant sloths – in far greater numbers than we see today.

Of course, it’s no secret that Homo sapiens used their ingenuity and incredible stamina to track down these massive meal tickets. But how often they fed on these herbivores was not so easy to determine.

Rather than relying solely on the fossil record or making tenuous comparisons to pre-agricultural cultures, the researchers turned to the evidence embedded in our own bodies and compared it with our closest cousins.

“We decided to use other methods to reconstruct the diet of Stone Age humans: to examine the memory preserved in our own bodies, our metabolism, our genetics and our physical constitution,” Ben-Dor said. .

“Human behavior changes rapidly, but evolution is slow. The body remembers.”

For example, compared to other primates, our body needs more energy per unit body mass. Especially when it comes to our energy-guzzling brains. Our social time, like when it comes to raising children, also limits the time we can spend foraging for food.

We have higher fat stores and can utilize them by quickly turning fat into ketones when the need arises. Unlike other omnivores, where fat cells are few but large, ours are small and numerous, echoing those of a predator.

Our digestive systems are also eerily similar to those of animals higher up the food chain. Having exceptionally strong stomach acid is exactly what we might need to break down proteins and kill harmful bacteria that you would expect to find on a week-old mammoth chop.

Even our genomes indicate a greater reliance on a meat-rich diet than on a sugar-rich diet.

“For example, geneticists concluded that areas of the human genome were closed off to allow a high fat diet, while in chimpanzees areas of the genome were open to allow a high sugar diet,” Ben-Dor said. .

The team’s argument is broad, touching on evidence of tool use, signs of trace elements and nitrogen isotopes in Paleolithic remains, and tooth wear.

Everything tells a story where the trophic level of our genus – gays position in the food web – has become very carnivorous for us and our cousins, homo erectusabout 2.5 million years ago, and remained so until the Upper Paleolithic about 11,700 years ago.

From here, studies of modern hunter-gatherer communities become a little more useful as declining populations of large animals and the fragmentation of cultures across the globe have led to greater consumption of plants, culminating in the Neolithic revolution in animal husbandry and agriculture.

None of this is to say that we should eat more meat. Our evolutionary past is no guide to human health and, as the researchers point out, our world is no longer what it used to be.

But knowing where our ancestors were in the food web has a big impact on understanding everything from our own health and physiology to our influence on the environment in the past.

This research was published in the American Journal of Physical Anthropology.

An earlier version of this article was first published in April 2021.

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