SALT LAKE CITY, May 2, 2011 - For decades, a 2.3 million- to 1.2 million-year-old human relative named Paranthropus boisei has been nicknamed Nutcracker Man because of his big, flat molar teeth and thick, powerful jaw. But a definitive new University of Utah study shows that Nutcracker Man didn't eat nuts, but instead chewed grasses and possibly sedges - a discovery that upsets conventional wisdom about early humanity's diet.
"It most likely was eating grass, and most definitely was not cracking nuts," says geochemist Thure Cerling, lead author of the study published in the May 2 online edition of the journal Proceedings of the National Academy of Sciences.
Study co-author Kevin Uno, a University of Utah Ph.D. student in geology, adds: "This study provides evidence that Paranthropus boisei was not cracking nuts, but was instead eating mainly tropical grasses or sedges. It was not competing for food with most other primates, who ate fruits, leaves and nuts; but with grazers zebras' ancestors, suids [ancestors of pigs and warthogs] and hippos."
Cerling and colleagues determined the extinct, upright-walking Paranthropus boisei's diet by analyzing carbon isotope ratios in the tooth enamel of 24 teeth from 22 individuals who lived between 1.4 million and 1.9 million years ago and were closely related to and once thought part of the genus of human ancestors named Australopithecus. Both extinct Paranthropus and the human genus Homo arose from Australopithecus.
University of Utah researchers Cerling and Uno conducted the study with three scientists from the National Museums of Kenya anthropologist Emma Mbua and paleontologists Francis Kirera and Fredrick Manthi and with Frederick Grine of Stony Brook University, anthropologist Matt Sponheimer of the University of Colorado at Boulder and famed anthropologist Meave Leakey, who is affiliated with the National Museums, Stony Brook and the Turkana Basin In
|Contact: Lee Siegel|
University of Utah