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May 04, 2011
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Ancient “Nutcracker Man” ate grass, not nuts, researchers say
May 4, 2011
Courtesy of the National Science Foundation
and World
Science staff
An ancient human relative that walked on two legs and sported a ridged skull may need a new nickname. Artist's reconstruction
of P. boisei. (Courtesy Nicolle Rager Fuller, Nat'l Science Foundation)
Paranthropus boisei, a 2.3 million to 1.2 million-year-old primate, whom researchers say is an early human cousin, probably didn’t crack nuts at all as his common handle, “Nutcracker Man,” suggests.
“Nutcracker Man” most likely ate grass and possibly sedges, a grasslike plant that grows in wet areas, said geochemist Thure Cerling, lead author of a study published in the May 2 online edition of the journal
Proceedings of the National Academy of Sciences.
Cerling, of the University of Utah, and colleagues studied P. boisei’s diet by analyzing the chemistry of the enamel of teeth from 22 members of the species. The hominid’s diet has been a source of scientific debate because his powerful jaws, huge molars and big, flat cheek teeth indicated he probably fed on nuts and seeds or roots and tubers found in the savannas throughout Eastern Africa. The crested skull is believed to have provided extra support for strong jaw muscles.
The conventional view of P. boisei’s diet started to fray a few years ago, when anthropologists at the University of Arkansas in Fayetteville highlighted inconsistencies with the common view by analyzing scratches and wear marks on the teeth. That team concluded the wear marks were more consistent with modern-day, fruit-eating animals than with most modern-day primates.
Cerling and his now team agree P. boisei wasn’t a big fan of nuts. “Wherever we find this creature, it is predominantly eating tropical grasses or perhaps sedges,” Cerling said.
Analysis of the proportions between varieties, or isotopes, of carbon in the tooth enamel indicate
P. boisei individuals preferred “C4” plants, which include grasses and sedges, said members of Cerling’s team. C4 plants use a specific chemical pathway to draw energy from sunlight, somewhat different from the so-called C3 pathway employed by most plants.
The diet now inferred for P. boisei looks about the same as the grass diets of grazing animals that lived at the same time: the ancestors of zebras, pigs, warthogs and hippos, said Cerling. “They were competing with them,” he said. “They were eating at the same table.”
“Frankly, we didn’t expect to find the primate equivalent of a cow dangling from a remote twig of our family tree,” added study co-author Matt Sponheimer, an anthropologist at the University of Colorado Boulder. “Fortunately for us, the work of several research groups over the last several years has begun to soften prevailing notions of early hominid diets. If we had presented our new results at a scientific meeting 20 years ago, we would have been laughed out of the room.”
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An ancient human relative that walked on two legs and sported a ridged skull may need a new nickname. Paranthropus boisei, a 2.3 million to 1.2 million-year-old primate, whom researchers say is an early human cousin, probably didn’t crack nuts at all as his common handle, “Nutcracker Man,” suggests. “Nutcracker Man” most likely ate grass and possibly sedges, a grasslike plant that grows in wet areas, said geochemist Thure Cerling, lead author of a study published in the May 2 online edition of the journal Proceedings of the National Academy of Sciences. Cerling, of the University of Utah, and colleagues studied P. boisei’s diet by analyzing the chemistry of the enamel of teeth from 22 members of the species. The hominid’s diet has been a source of scientific debate because his powerful jaws, huge molars and big, flat cheek teeth indicated he probably fed on nuts and seeds or roots and tubers found in the savannas throughout Eastern Africa. The crested skull is believed to have provided extra support for strong jaw muscles. The conventional view of P. boisei’s diet started to fray a few years ago, when anthropologists at the University of Arkansas in Fayetteville highlighted inconsistencies with the common view by analyzing scratches and wear marks on the teeth. That team concluded the wear marks were more consistent with modern-day, fruit-eating animals than with most modern-day primates. Cerling and his now team agree P. boisei wasn’t a big fan of nuts. “Wherever we find this creature, it is predominantly eating tropical grasses or perhaps sedges,” Cerling said. Analysis of the proportions between varieties, or isotopes, of carbon in the tooth enamel indicated P. boisei individuals preferred “C4” plants, which include grasses and sedges, said members of Cerling’s team. C4 plants use a specific chemical pathway to draw energy from sunlight, somewhat different from the so-called C3 pathway employed by most plants. The diet inferred for P. boisei looks about the same as the grass diets of grazing animals that lived at the same time: the ancestors of zebras, pigs, warthogs and hippos, said Cerling. “They were competing with them,” he said. “They were eating at the same table.” “Frankly, we didn’t expect to find the primate equivalent of a cow dangling from a remote twig of our family tree,” added study co-author Matt Sponheimer, an anthropologist at the University of Colorado Boulder. “Fortunately for us, the work of several research groups over the last several years has begun to soften prevailing notions of early hominid diets. If we had presented our new results at a scientific meeting 20 years ago, we would have been laughed out of the room.”