
By Sama Marwan,
A study conducted on the teeth of human ancestors who lived around 3.5 million years ago revealed that these early humans were vegetarians. The consumption of animal foods, such as meat, is considered a pivotal turning point in human evolution, as archaeologists link it to brain growth and the development of tool-making and usage.
According to Newsweek, it is difficult to find evidence pinpointing exactly when prehistoric people began eating meat. Australopithecus, a hominin that resembled humans, walked on two legs but had a smaller brain than both Neanderthals and modern humans.
In this study, scientists from the Max Planck Institute for Chemistry in Germany and the University of the Witwatersrand (Wits) in South Africa analyzed different nitrogen isotopes found in the enamel of fossilized teeth of seven Australopithecus individuals discovered in South Africa.
When animals digest food, their bodies tend to use and excrete a lighter form of nitrogen called 14N through urine, feces, and sweat, leaving behind more of the heavier nitrogen isotope, 15N, in their bodies compared to the food they consume.
This means that plants contain a lot of 14N but not much 15N. Herbivores have more 15N and less 14N in their bodies compared to the plants they eat, while carnivores have a lot of 15N and not much 14N.
Therefore, the higher the 15N content in an animal’s body compared to the 14N, it is believed to be higher in the food chain. Nitrogen isotope ratios have long been used to study the diets of both modern humans and animals, for example, through their hair and bones.