primordial human ancestors adhered to a plant-based diet, approximately three million years in the past.
Revised Article:
Our ancient relatives, the Australopithecus, went veggie 3.5 million years ago,. according to some new research. Researchers from the Max Planck Institute for Chemistry in Germany and the University of the Witwatersrand in South Africa dug into the lion's share of plant-based diets of our early hominin buddies. This discovery was published in the prestigious journal Science.
This groundbreaking investigation analyzed nitrogen isotopes found in fossilized tooth enamel of seven Australopithecus specimens. The results? Primarily plant-based goodies, with little to no evidence of munching on meat.
Meat has long been defined as a significant turning point in human evolution, fueling growth in brain volume and tool development. But precisely when and how meat entered our ancestors' diets has remained a puzzle.
These German and South African scientists examined tooth enamel from Australopithecus fossils found in the Sterkfontein cave near Johannesburg—a renowned archaeological site in South Africa's "Cradle of Humankind." They compared these isotopic data with samples from contemporary animals like monkeys, antelopes, and carnivores like hyenas, jackals, and big cats.
Tooth enamel is the dietary historian
As geochemist Tina Lüdecke, the lead author of the study, puts it, "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." Tina has been analyzing fossilized teeth for her research since 2021, and as an Honorary Research Fellow at the Evolutionary Studies Institute of the University of the Witwatersrand, she frequently travels to Africa for that purpose. The Sterkfontein Caves, owned by Wits University, are home to the Australopithecus fossils under investigation.
When animals break down food, processes prefer lighter nitrogen isotopes (N). The resulting degradation products then contain high amounts of these lighter isotopes within the body. As these "light" nitrogen compounds are excreted in urine, feces, or sweat, the body's ratio of heavy nitrogen (N) to lighter nitrogen increases in comparison to the food eaten. This is why herbivores have higher nitrogen isotope ratios than the plants they consume, while carnivores have higher ratios than their prey. Consequently, a higher N to N ratio in a tissue sample indicates a higher trophic position within the food chain.
Pointing to a plant-based diet
The researchers' findings? The nitrogen isotope ratios in the tooth enamel of Australopithecus varied, but they were always low and similar to those of herbivores. This means our early ancestors primarily chowed down on plants, with no signs of regular meat consumption. In fact, they didn't seem to dine on large mammals like their meat-loving successors, the Neanderthals.
While the analysis didn't rule out occasional nibbles on animal protein sources like eggs or termites, the evidence points to a predominantly vegetarian diet. The researchers plan to collect more data from diverse hominin species and time periods to further justify this theory and explore when and how meat entered the human menu.
This ground-breaking method may unlock exciting possibilities for understanding our evolutionary past. "The work 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," explains Alfredo Martínez-García, a researcher at the Max Planck Institute for Chemistry. Stay tuned for more discoveries as researchers continue to delve into our paleodietary past!
- The research published in Science has shown that Australopithecus, our ancient relatives, shifted towards a plant-based diet around 3.5 million years ago, indicating a minor role for fitness-and-exercise related activities like hunting in their health-and-wellness routines.
- The scientists' study, focusing on the nitrogen isotopes in tooth enamel, reveals that environmental-science factors, such as the climate-change scenarios of their time, influenced the dietary choices of these early hominins, with less reliance on space-and-astronomy-related resources such as meat.
- The research reinforces the significance of nutrition in the context of human evolution, suggesting that our ancestors' diet adjustments were a response to their natural environment and surrounding vegetation, rather than advances in environmental-science or space-and-astronomy technologies.
