Richard L. McCormick Interim President | Stony Brook University
Richard L. McCormick Interim President | Stony Brook University
An international team of researchers has discovered that Australopithecus, an ancient human ancestor living over three million years ago in South Africa, primarily consumed plant-based foods. This finding was published in the journal Science and is based on the analysis of tooth enamel from seven Australopithecus fossils. The research challenges previous assumptions about the role of meat consumption in the evolution of brain size among early hominins.
The study included contributions from Dominic Stratford of Stony Brook University and the University of the Witwatersrand, along with investigators from the Max Planck Institute for Chemistry (MPIC) in Germany. The researchers analyzed stable nitrogen isotope data from Australopithecus fossils found at Sterkfontein Caves, a site known for its rich collection of early hominin fossils.
Stable nitrogen isotopes are used to determine an animal's position in the food chain, with higher 15N levels indicating a diet that includes more animal tissue. Traditionally, bone collagen or dentin were sampled for such analyses, but these materials decay quickly, limiting their usefulness to around 300,000 years. Advances in analytical techniques now allow for sampling enamel, which can preserve dietary isotopic fingerprints for millions of years.
According to Stratford — an adjunct lecturer at Stony Brook’s College of Arts and Sciences and director of research at Sterkfontein Caves — this advancement allowed researchers to obtain direct evidence about ancient hominin diets and investigate when meat consumption began as a behavior influencing human evolution.
Comparing isotopic data from Australopithecus with other contemporary animals like monkeys and big cats showed that while occasional meat consumption was possible, their primary diet was plant-based. The findings suggest changes in Australopithecus behavior might not be linked to increased meat consumption. Regular meat eating may 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. "It represents a huge step in extending our ability to better understand diets and trophic level of all animals back into the scale of millions of years.”