A new study of early human ancestors who lived millions of years ago shows that they were largely vegetarian, although stone tools and animal bones have been found during the same period.

this Work Marks an important advance in researchers' ability to reconstruct ancient diets, as it involves developing a new way to look inside tooth enamel to look for evidence of meat-eating.

Paleoanthropologists are particularly interested in meat because they believe that access to an abundance of high-protein foods was crucial to the evolution of larger, more complex human brains.

"To power these big machines in our brains, we need a lot of energy, so of course we need high-quality, energy-rich foods," explains Tina LuedeckerScientist at the Max Planck Institute of Chemistry in Germany.

She said researchers have long known how to look for chemical signatures related to the consumption of different types of plants, such as grasses versus trees, and use them on ancient sites, "just to understand who was out in the open grasslands and who was at the ancient sites superior". Live more in forest environments. "

But chemical tests used to detect plant consumption don't reveal meat consumption, Luedecker said, "and I'm always very frustrated, like many of us - where's the meat?"

Recently, she and her colleagues developed a new, highly sensitive chemical analysis method that can detect signs of a meat-heavy diet. The test involves detecting very, very small amounts of nitrogen in trace amounts of organic material preserved in tooth enamel.

Researchers just used it to study a study called Australopithecus australopithecus, Lived approximately 3 million years ago.

"These were still fairly ape-like, small-brained hominids that could already walk upright, but in a more ape-like manner," she said.

She obtained permission to collect samples from Australopithecus The remains were found in a cave in South Africa, and dental drills were used to remove enamel fragments from teeth belonging to seven individuals.

When her team analyzed the samples and compared them with results from known carnivores and herbivores, they found that "all seven of these individuals likely did not consume large amounts of meat," she said. "These are mostly plant-based animals."

They may have eaten some energy-rich foods such as beans or termites that were not detected by such tests, but the results were published in a journal sciencemaking it clear that they are not living a carnivore lifestyle.

"Here, for the first time, we have actual data to say, 'Okay, these small-brained humans didn't consume much meat,'" Luedecker said. "But what happens after that, right?"

She wants to run the same test on other past human relatives to move up the evolutionary chain.

This work is an important step in the reconstruction of ancient diets, says Bernard WoodPaleoanthropologist at George Washington University. He was not a member of the research team but called himself a "big fan" of the new study.

"This means people could look at other ancient humans and try to make the same measurements and try to understand the food they consumed throughout their lives," he said.

For example, he wants to know a handy manan extinct human species that lived about two million years ago.

"It would be nice to know if a handy man "I eat as much meat as some people think," he said, "and I doubt it."

Conventional Wisdom About Australopithecus In the past, it was thought to be a carnivore, but this study shows it "doesn't appear to eat any more meat than a group of living primates and some chimpanzees do," he said.