Our ancestors were vegetarians three million years ago

Human ancestors like Australopithecuswho lived about 3.5 million years ago in southern Africa, ate very little or no meat, reveals a new study published in ‘Science’.

This conclusion comes from an analysis of nitrogen isotopes in the fossilized tooth enamel of seven Australopithecus individuals. The data revealed that these early hominids relied primarily on plant-based diets, with little to no evidence of meat consumption.

He consumption of animal resourcesespecially meat, It is considered a crucial turning point in human evolution. This protein-rich food has been linked to increased brain volume and the ability to develop tools. However, the evidence directly from when meat emerged among our first ancestors, and how its consumption developed over time, has been elusive.

A team of researchers from the Max Planck Institute of Chemistry in Germany and the University of the Witwatersrand in South Africa now provides evidence that human ancestors of the genus Australopithecus who lived in southern Africa between 3.7 and 3.3 million years ago They subsisted mainly on plants.

The research team analyzed stable isotope data from tooth enamel of Australopithecus individuals found in Sterkfontein Cave near Johannesburg, part of South Africa’s ‘Cradle of Humankind’, an area known for its rich collection of early hominid fossils. They compared isotopic data from Australopithecus with those from tooth samples from co-occurring animals, including monkeys, antelopes and large predators such as hyenas, jackals and big cats.

“Tooth enamel is the hardest tissue in the mammalian body and can preserve the isotopic signature of an animal’s diet during millions of years”says geochemist Tina Lüdecke, lead author of the study, in a statement.

When animals digest food, biochemical reactions favor the “light” isotope of nitrogen (14N). Consequently, the breakdown products produced in your body contain high proportions of 14N. Excretion of these “light” nitrogen compounds in urine, feces or sweat increases the ratio of “heavy” nitrogen (15N) to this “light” nitrogen in the body compared to the food you eat.

This means that herbivores have a higher nitrogen isotope ratio than the plants they consume, while carnivores in turn have a higher nitrogen isotope ratio than their prey. Therefore, the higher the ratio of 15N to 14N in a tissue sample, the higher the trophic position of the organism in the food web.

Nitrogen isotope ratios have long been used to study the diets of modern animals and humans in hair, claws, bones, and many other organic materials. However, in fossil material, these measurements have previously been limited to samples that are only a few tens of thousands of years old due to the degradation of organic material over time.

In this study, Tina Lüdecke used a novel technique developed in the laboratory of Alfredo Martínez-García at the Max Planck Institute of Chemistry, to measure nitrogen isotopes. Varying but consistently low nitrogen isotope ratios have been found in the enamel of fossilized teeth, which are millions of years old, similar to those of herbivores and much lower than those of contemporary carnivores.

They conclude that The diet of these hominids was variable, but consisted largely or exclusively of foods of plant origin. Therefore, the Australopithecus did not regularly hunt large mammals as, for example, the Neanderthals did a few million years later. While researchers cannot completely rule out the possibility of occasional consumption of animal protein sources such as eggs or termites, evidence indicates a predominantly vegetarian diet.