National Geographic News
A model of a Tyrannosaurus rex skull.
The recontructed skull musculature of a South Dakota T. rex (file picture).

Photograph by Ira Block; model by Brian Cooley

Charles Q. Choi

for National Geographic News

Published February 28, 2012

Once the largest known carnivore on land, Tyrannosaurus rex also had the most powerful bite of any terrestrial animal of any time period, a new study suggests.

(Related video: "T. Rex's Bone-Shattering Bite Filmed.")

Much conventional wisdom about the world's most famous dinosaur species has been called into question in recent years—for instance, whether the 40-foot-long (12-meter-long) T. rex species could run or only plod along.

Likewise, some have contended that the supposedly mighty predator actually had a modest bite, limiting T. rex to scavenging.

To see how forcefully T. rex could bite, biomechanicists involved in the new study used laser scanners to digitize juvenile and adult T. rex skulls. The team then used computer models to reconstruct the dinosaur's jaw muscles and analyze bite performance.

The models suggest that an adult T. rex was capable of a maximum bite force of 35,000 to 57,000 newtons at its back teeth. That's more than four times higher than past estimates and ten times as forceful as the bite of a modern alligator.

T. rex, which went extinct about 65 million years ago, "probably lives up to its reputation as a ferocious biter," concluded study leader Karl Bates, a computational anatomist at the University of Liverpool in the United Kingdom.

(Also see "New 'Destroyer' Dinosaur Found—Was T. Rex Relative.")

T. Rex No Match for Megatooth?

Although T. rex may have possessed the most powerful bite of any land animal, it apparently paled in comparison to that of prehistoric megalodon—literally "megatooth"—sharks, which may have grown to lengths of more than 50 feet (16 meters) and weighed up to 30 times more than the largest great white.

Past megalodon research suggests these giant marine predators, which first appeared around 16 million years ago, could chomp with more than three times the force of T. rex, based on the new figures.

The bite force of a megalodon—"just because it was so much larger-bodied—would have been bigger," Bates said.

So T. rex could have bitten with ten times the force of an alligator. But would it have?

Answering that question would require an estimate of how much stress T. rex's skull could take, Bates said—to help pinpoint just how forcefully the predator could have bitten down with without hurting itself.

The T. rex bite study will be published online February 29 in the journal Biology Letters.



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