Tuesday, October 19, 2010

Tyrannosaurus Rex: the cannibal


Tyrannosaurus Rex: the cannibal
Tyrannosaurus Rex's reputation as a cold blooded killer just got worse – the prehistoric predators feasted on each other, scientists believe.
Richard Alleyne, Science Correspondent
15 Oct 2010

The seven tonne monsters, which at 13 feet tall and 40 feet long were the largest land predators to ever to stalk the earth, were cannibals, a new study has found.

Paleontologists noticed bite marks on the bones of the dinosaurs, and on examining the huge gouges realised T-Rex was the only carnivore large enough to have caused them.

Scientists are sure that the marks were caused by feeding rather than combat, although it is not clear whether the carcass was scavenged or devoured after a clash with another T-Rex 65 million years ago.

The winner may have eaten the loser, said Yale University researcher Dr Nick Longrich.

He said: "It is the first evidence of cannibalism but in a way it is not surprising. Modern big carnivores like lions and alligators do this all the time.

"It's a convenient way to take out the competition and get a bit of food at the same time. "

The marks seem to have been made after death, suggesting that the predator may have eaten the most accessible meat after the kill before returning to gnaw at the bones.

Dr Longrich said the find was an important clue into the eating habits of T-rex, whose name means tyrant lizard king and unlike today's large carnivores hunted alone rather than in packs.

He said: "These animals were some of the largest terrestrial carnivores of all time, and the way they approached eating was fundamentally different from modern species.

"There's a big mystery around what and how they ate, and this research helps to uncover one piece of the puzzle."

Dr Longrich made the breakthrough while looking through fossil collections for mammal tooth marks, and finding one bone, excavated in western America, with particular large gouges, reports journal PLoS ONE.

He said: "They're the kind of marks that any big carnivore could have made, but T. rex was the only big carnivore in western North America 65 million years ago."

It was only after establishing the bite marks were from a T-Rex that he realised the bone itself was also from the behemoth.

He turned his study to other T-Rex bones and found similar evidence on cannibalism.

He said: "It's surprising how frequent it appears to have been."

Only one other dinosaur species, Majungatholus, is known to have been a cannibal, but Dr Longrich believes further study could show the practice was more widespread than is currently believed.

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