Over 3 Million Years Ago, Our Ancestors Were Mainly Vegetarian
One of our earliest ancestors, who lived around 3.5 million years ago, stuck to a mostly vegetarian diet. The ancient hominin, Australopithecus, inhabited eastern and southern Africa.
These prehistoric people walked on two legs but had smaller brains compared to Neanderthals and modern humans.
Archaeologists link the consumption of meat to the growth of the brain and the development and use of tools. But evidence of when they started eating meat has been hard to find.
In a new study, scientists from the Max Planck Institute for Chemistry in Germany and the University of Witwatersrand in South Africa analyzed the fossilized teeth of seven Australopithecus individuals found in the Sterkfontein cave near Johannesburg in southern Africa. This cave is part of a system of archaeological sites and is known for containing early hominin fossils.
The team developed a new technique to measure nitrogen isotope ratios in tooth enamel, which has been helpful in studying ancient diets.
Then, they compared the data to isotopic data from tooth samples of coexisting animals like monkeys, antelopes, and hyenas to determine where Australopithecus was on the prehistoric food chain.
“Tooth enamel is the hardest tissue of the mammalian body and can preserve the isotopic fingerprint of an animal’s diet for millions of years,” said Tina Lüdecke, a geochemist and the lead author of the study from Max Planck.
The researchers found that the nitrogen isotope ratios in the tooth enamel of Australopithecus were low. They were similar to the ones examined in herbivores but lower than the ones in modern carnivores. This suggests that the diet of Australopithecus consisted primarily of plant-based foods.
They did not hunt large animals for consumption, which is an activity that appeared a few million years later with Homo erectus and Neanderthals.
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Australopithecus may not have eaten meat from larger animals, but it is possible that they still ate some sources of animal protein, such as eggs or termites.
In the past, research showed that Australopithecus afarensis, a species of australopithecine that lived in eastern Africa from about 3.9 million years to three million years ago, likely had a diet of grasses, sedges, and succulents that are usually found in deserts and tropical savannas.
Since Australopithecus had a vegetarian diet, they certainly were not the turning point of early humans evolving to eat meat-based diets. Now, researchers can move on to studying different hominin species.
The team plans to analyze fossils from other sites across southern and eastern Africa, as well as southeast Asia, to search for clues on the origins of human meat consumption.
“This method opens up exciting possibilities for understanding human evolution, and it has the potential to answer crucial questions, for example, when did our ancestors begin to incorporate meat in their diet? And was the onset of meat consumption linked to an increase in brain volume?” said Alfredo Martínez-García, a geochemist from Max Planck.
The study was published in the journal Science.
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