Unveiling Our Primal Past: The Surprising Herbivorous Habits of Early Humans

Some of our species’ earliest predecessors might have devoted significantly more time to consuming plant-based meals rather than meat.

A study of the chemical makeup of fossilized teeth from Australopithecus africanus — a primitive ancestor of humans — indicates that these bipedal primates primarily followed plant-based diets, as detailed by researchers in the January 17 edition of Science. These results offer direct proof of the position held by one of humanity’s earliest ancestors within its surrounding food chain over 3 million years in the past.

Nutrition has played an essential role in human evolution, states Tina Lüdecke, a geochemist at the Max Planck Institute for Chemistry located in Mainz, Germany. It is speculated that transitioning from a plant-based diet to regularly eating high-protein items such as meat was a driving force behind the advancement of humans’ cognitive abilities.

“These premium-quality sustenances grant us substantial energy, which is essential for fueling our significant brains,” Lüdecke states.

The exact moment of this nutritional alteration remains ambiguous. To gain further insights into diets from the distant past, Lüdecke and her associates extracted samples “`out of the dentition of 43 approximately 3.5-million-year-old fossilized mammals from the Sterkfontein caves in South Africa, including seven distinct A. africanus specimens. Encased within the matrix of dental enamel are minuscule fragments of nitrogen-containing organic materials, which disclose insights about ancient nutrition, as the ratio of two nitrogen forms is correlated to the relative quantity of meat consumed during life. 

Upon analyzing the enamel nitrogen ratios from A. africanus in comparison with those of other extinct mammals from Sterkfontein and current African mammals, it appears that the early humans maintained a varied diet, although not one abundant in mammalian flesh. These discoveries may have ramifications for how scholars perceive the role of meat consumption in the development of other human characteristics. For example, adaptations in Australopithecus, such as shorter snouts, bipedal movement, and the capability to flourish in a savanna habitat may have occurred prior to the transition to a brain-enhancing meat-rich diet. 

Lüdecke emphasizes that the results do not imply that A. africanus could not have occasionally taken advantage of a meaty feast. The findings also do not exclude the possibility of the primates consuming a considerable number of termites—a dependable, high-energy source of food—since they contain relatively lower amounts of the nitrogen form prevalent in mammalian meat. “We observe that apes today [forage for termites], so why not our ancestors?”

With baseline data now established, Lüdecke indicates that forthcoming studies could apply the same techniques to the teeth of other later human species to explore how diets might have evolved over millions of years.