New evidence suggests that certain early human ancestors rarely consumed meat, adding new information to the timeline of human evolution.

Tooth enamel from seven Australopithecus fossils and surrounding mammals were analyzed and

cross-referenced with one another, and the results revealed that our early relatives matched those of other known herbivore species.

Tina Lüdecke, a geochemist at the Max Planck Institute for Chemistry in Germany, has been working with colleagues to develop a new method to analyze diet from tooth enamel.

In 2021, this method proved a success in feeding simulations with guinea pigs, opening up a wide range of possibilities for new fossil analysis. While previously difficult to analyze, tooth enamel holds nitrogen indicators of organic material for millions of years. This is much longer than collagen from bones or dentin, the sources that former methods relied on.

Fast forward to now, when Lüdecke led a team that delicately drilled tooth samples from 43 fossilized mammals in Sterkfontein caves in South Africa. They concluded that Australopithecus were predominantly plant-eaters, with some exceptions for insects.

Lüdeke told ScienceNews, “We see that apes nowadays [fish for termites], so why not our ancestors?” Regardless, few indicators for mammalian meat were found.

Having definitive evidence of diet is crucial for evolutionary scientists, as they piece together the occurrence of pivotal events that shaped our phylogenetic relationships. In 2010, the discovery of one of the earliest stone tools, presumably for meat consumption was attributed to Australopithecus afarensis, though it seems other members of the genus preferred salad.

Eating mammal meat is credited as one of the largest driving forces that allowed our ancestors to have larger brains. “To power these big machines in our heads, we need a lot of energy, so of course we need high-quality, energy-rich foods,” Lüdecke said on NPR.

These results, particularly from this new method of analysis, have caught the attention of paleontologists and evolutionary scientists alike.

Bernard Wood, paleoanthropologist and Professor of Human Origins at The George Washington University, hopes future studies will focus on early ancestor species with larger brains.

“It would be great to know whether Homo habilis was eating as much meat as some people think it was,” said Wood to NPR. “I have my doubts.”

Lüdecke said she is looking forward to learning more as well. “Here, for the first time, we have actual numbers to put on there to say, ‘Ok, not much meat was consumed for these small-

brained hominins,’” she said. “But then what happened after, right?”