Washington, June 4 (ANI): A new look at the diets of ancient African hominids shows a "game changer" occurred about 3.5 million years ago when some members added grasses or sedges to their menus.
Lead study author CU-Boulder anthropology Professor Matt Sponheimer said that high-tech tests on tooth enamel by researchers at the University of Colorado Boulder indicate that prior to about 4 million years ago, Africa's hominids were eating essentially chimpanzee style, likely dining on fruits and some leaves.
Despite the fact that grasses and sedges were readily available back then, the hominids seem to have ignored them for an extended period, he said.
"We don't know exactly what happened. But we do know that after about 3.5 million years ago, some of these hominids started to eat things that they did not eat before, and it is quite possible that these changes in diet were an important step in becoming human," Sponheimer said.
The new research provides detailed information on the teeth of 88 additional specimens, including five previously unanalyzed hominid species, doubling the dataset, he said.
While the hominids from the genus Homo that evolved from australopithecines like the 3 million-year-old fossil Lucy-considered by many the matriarch of modern humans-were broadening their food choices, a short, upright hominid known as Paranthropus boisei that lived side by side with them in eastern Africa was diverging toward a more specific, C4 diet.
Scientists initially had dubbed P. boisei "Nutcracker Man" because of its large, flat teeth and powerful jaws, but recent analyses indicate it might have instead used its back teeth to grind grasses and sedges, Sponheimer said.
"We now have the first direct evidence that as the cheek teeth on hominids got bigger, their consumption of plants like grasses and sedges increased," he said.
"We also see niche differentiation between Homo and Paranthropus-it looks probable that Paranthropus boisei had a relatively restricted diet, while members of the genus Homo were eating a wider variety of things.
The study is published online by the Proceedings of the National Academy of Sciences. (ANI)