An international team of researchers has uncovered new insights into the diet of ancient human ancestors. The study, published in the journal Science, involved an analysis of tooth enamel from seven Australopithecus fossils found in the Sterkfontein Caves in South Africa. This species lived more than three million years ago and primarily consumed plant-based foods.
The research was led by Dominic Stratford from Stony Brook University and the University of the Witwatersrand, alongside scientists from the Max Planck Institute for Chemistry. Their work focused on stable nitrogen isotope data (15N/14N) extracted from the fossils' tooth enamel. This method allowed them to infer the dietary habits of these early hominins.
Nitrogen isotope analysis has long been used to determine an animal's position in the food chain, with higher levels indicating meat consumption. Traditional techniques relied on bone collagen or dentin, which decay relatively quickly, limiting their usefulness to around 300,000 years. However, recent advancements have enabled researchers to analyze enamel, which can preserve dietary isotopes for millions of years.
According to Stratford, "this advancement in nitrogen isotope analysis enabled the researchers to obtain the first direct evidence of the diet of ancient hominin fossils and explore when meat eating started." The study compared isotopic data from Australopithecus with that of contemporary animals like monkeys and big cats.
The findings suggest that while Australopithecus may have occasionally eaten meat, its diet was largely herbivorous. Stratford noted that this could mean changes in behavior seen in Australopithecus were not driven by increased meat consumption. Instead, regular meat eating might have emerged later or elsewhere.
“Overall, this work provides clear evidence that Australopithecus in South Africa did not eat significant amounts of meat three million years ago," said Stratford. This research marks a significant step toward understanding ancient diets and evolutionary shifts over millions of years.