"Long before it's in the papers"
June 03, 2013

RETURN TO THE WORLD SCIENCE HOME PAGE


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.

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.

Artist's re­con­struc­tion of P. boi­sei. (Cour­te­sy Nicolle Rager Full­er, Nat'l Sci­ence Founda­tion)


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.”


* * *

Send us a comment on this story, or send it to a friend









 

Sign up for
e-newsletter
   
 
subscribe
 
cancel

On Home Page         

LATEST

  • Meet­ing on­line may lead to hap­pier mar­riages

  • Pov­erty re­duction, environ­mental safe­guards go hand in hand: UN re­port

EXCLUSIVES

  • Was black­mail essen­tial for marr­iage to evolve?

  • Plu­to has even cold­er “twin” of sim­ilar size, studies find

  • Could simple an­ger have taught people to coop­erate?

  • Diff­erent cul­tures’ mu­sic matches their spe­ech styles, study finds

MORE NEWS

  • F­rog said to de­scribe its home through song

  • Even r­ats will lend a help­ing paw: study

  • D­rug may undo aging-assoc­iated brain changes in ani­mals

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.”