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July 15, 2013

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A reputation sealed? Finding suggests T. rex hunted for real

July 15, 2013
Courtesy of PNAS
and World Science staff

A toothy dis­cov­ery sug­gests the icon­ic di­no­saur Ty­ran­no­saur­us rex was a real hunt­er af­ter all—not a mere scav­en­ger, as some sci­entists have ar­gued.

Sci­en­tists found a T. rex tooth crown found lodged in the tail bones of a plant-eating di­no­saur about 8 me­ters (26 feet) long. The an­i­mal was clearly alive at the time of the bite, as healed bone proves it sur­vived the at­tack, re­search­ers said.

Re­search­er Da­vid A. Burn­ham uses a pen­cil to point out a Ty­ran­no­saur­ rex tooth crown em­bed­ded be­tween had­ro­saur ver­te­brae and sur­rounded by bone over­growth. (Cour­te­sy Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces)


Pa­le­on­tol­ogists have long de­bat­ed wheth­er T. rex, a car­ni­vore from the Late Cre­ta­ceous pe­ri­od, was the feared pred­a­tor of leg­end or a scav­en­ger that fed on car­ri­on. 

Da­vid A. Burn­ham from the Palm Beach Mu­se­um of Nat­u­ral His­to­ry in Flor­i­da re­ported the find­ings in this week’s early on­line is­sue of the jour­nal Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces. They ar­gued that the loca­t­ion of the in­jury—in the south­bound end of a north­bound victim—sug­gests T. rex was chas­ing the an­i­mal. 

The find­ing is “defini­tive ev­i­dence of preda­t­ion,” they wrote. But they em­pha­sized that it does­n’t mean T. rex did­n’t scav­enge for dead meat at all; most large pred­a­tors do, they not­ed.

The fos­sil­ized bones came from the Hell Creek forma­t­ion of Har­ding Coun­ty, South Da­ko­ta. A nor­mal adult T. rex would have been some­what larg­er than the vic­tim­ized plant-eater, iden­ti­fied as a type of di­no­saur called a had­ro­saur.

T. rex, one of the larg­est meat-eating di­no­saurs, lived about 85 to 65 mil­lion years ago, at which time it died out along with oth­er “non-avian” di­no­saurs. 

Pre­vi­ous stud­ies found what ap­peared to be T. rex stom­ach con­tents con­tain­ing young had­ro­saur bones, but this did­n’t re­veal wheth­er the an­i­mals were dead or alive when eat­en.


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A toothy discovery suggests that the iconic dinosaur species Tyrannosaurus rex was a real hunter after all—not a mere scavenger, as some recent studies indicate. Scientists found a T. rex tooth crown found lodged in the tail bones of a plant-eating dinosaur about 8 meters (26 feet) long. The animal was alive at the time of the bite because healed bone proves it survived the attack, researchers said. Paleontologists have long debated whether T. rex, a carnivore from the Late Cretaceous period, was the feared predator of legend or a scavenger that fed on carrion. David A. Burnham from the Palm Beach Museum of Natural History in Florida reported the findings in this week’s early online issue of the journal pnas. They argued that the location of the injury—in the southbound end of a northbound hadrosaur—suggests that T. rex may have been pursuing the animal when it was bitten. The finding is “definitive evidence of predation,” they wrote. But they emphasized that it doesn’t mean T. rex didn’t scavenge for dead meat at all; most large predators do, they noted. The fossilized bones came from the Hell Creek formation of Harding County, South Dakota. A normal adult T. rex would have been somewhat larger than the victimized plant-eater, identified as a type of dinosaur called a hadrosaur. T. rex, one of the largest meat-eating dinosaurs, lived about 85 to 65 million years ago, at which time it died out along with other “non-avian” dinosaurs. Previous studies found what appeared to be T. rex stomach contents containing young hadrosaur bones, but this didn’t reveal whether the animals were dead or alive when eaten. n