Researchers examined the teeth of Paranthropus boisei, also called the "Nutcracker Man," an ancient hominin that lived between 2.3 and 1.2 million years ago. The "Nutcracker Man" had the biggest, flattest cheek teeth and the thickest enamel of any known human ancestor and was thought to have a regular diet of nuts and seeds or roots and tubers. But analysis of scratches on the teeth and other tooth wear reveal the pattern of eating for the "Nutcracker Man" was more consistent with modern-day fruit-eating animals.

Credit: Nicolle Rager Fuller, National Science Foundation

The skull of Paranthropus boisei, also know as the "Nutcracker Man," left, had large teeth, indications of big chewing muscles and thick tooth enamel compared to the skulls of modern-day humans, on the right. Research shows that despite their teeth's large size, the "Nutcracker Man" may not have had a regular diet of hard foods like nuts and seeds or roots and tubers.

Credit: Photo by Melissa Lutz Blouin, University of Arkansas

Lead researcher Peter Ungar, professor of anthropology at the University of Arkansas in Fayetteville, took dental impressions from the teeth of ancient hominins, such as Lucy, shown here, to make dietary comparisons with other human ancestors such as the Nutcracker Man.

Credit: Peter Ungar, University of Arkansas

Peter Ungar, professor of anthropology at the University of Arkansas, describes how microscopic pits and scratches on teeth are signs of eating hard foods like nuts or tough foods like leaves. The pits and scratches are clues to the evolution of early human ancestor diet.

Credit: National Science Foundation