While the modern day debate about humanity's access to grass remains a hot button political issue, our ancient hominid ancestors showed no hesitation including the vegetation as a staple of their diet and diverging from their ape-like heritage 3.5 million years ago.
The transition from simple fruits and leaves to grasses and potentially herbivores marks a decisive split from the habits of the primates that we know if our times, and allegedly explains why so many human-like species were able to co-exist: "they were not competing for the same foods," says Thure Cerling of the University of Utah.
Scientists studied the remains of several human species by examining the carbon isotopes trapped in the teeth of nearly 200 specimens.
Zeresenay Alemseged, a professor at the California Academy of Sciences, explains that "because feeding is the most important factor determining an organism's physiology, behaviour and its interaction with the environment, these finds will give us new insight into the evolutionary mechanisms that shaped our evolution."
Over time, hominids displayed a preference to food from the Savannahs as opposed to the forest. The University of South Florida's Dr. Jonathan Wynn suggests, "Exploring new environments and testing new foods, ultimately might be correlated with further changes in human history."
Cerling adds, "If diet has anything to do with the evolution of larger brain size and intelligence, then we are considering a diet that is very different than that we were thinking about 15 years ago."
The quartet of studies which publicized these discoveries were published in the PNAS journal, according to BBC News.