It might be true for yappy dogs, but it is almost impossible to imagine that the bark of Tyrannosaurus rex was worse than its bite.
A new study indicates that the roughly 60 teeth of the supposed king of dinosaurs exerted a biting force nearly 25 times that of a Labrador dog, 18 times that of the average human, nine times that of a dusky shark, four times that of a karate chop and three times that of a lion.Among modern animals, only the alligator was a biting match for the tyrannosaurus.
We know this because scientists at the University of California-Berkeley and Stanford University measured the tyrannosaurus bite force with a guillotine-like machine that bit into cow bones with a set of aluminum-bronze, simulated T. rex teeth.
The impetus for the study, reported in the magazine Nature, was the discovery in Montana in 1991 of a triceratops pelvis that a hungry Tyrannosaurus rex gnawed up and down 70 million years ago. In all, 58 definite and 22 probable teeth marks were found on a pelvis that was roughly the size of a shower-stall floor.
Several lines of evidence suggested a Tyrannosaurus rex had dined on the triceratops. When a cast was made of one puncture, it produced an almost exact copy of the canine-type teeth of Tyrannosaurus rex. The animal eating the triceratops left distinctive, T. rex teeth serrations as it scraped the pelvis.
And finally, the only fossil remains in the area of an animal big enough to create the teeth marks belonged to the dinosaur king, some of whose teeth were 6 inches long.
Armed with bite depths and measures of fossilized Tyrannosaurus rex teeth, the California scientists decided to see how much force was needed to break bones to the depth observed. An examination of the triceratops pelvis revealed that it was similar in growth form and structure to the pelvis of the modern cow. So cow bones were artificially chewed upon and the bite marks that appeared were remarkably like those that appeared in the triceratops.
Measurements indicated that the Tyrannosaurus rex exerted a force of up to about 3,000 pounds.
Only the American alligator equalled the Tyrannosaurus rex's powerful jaws.
In addition to simply being interesting and curious, the researchers say, the new biting numbers suggest that the T. rex may have been a predator and not a scavenger.
Throughout the debate, which has raged for nearly a century, some experts have argued that dinosaurs ate dead animals because their jaws and teeth were too weak to strike down living creatures.
"The teeth were as strong as those of an alligator, a predator that frequently has to deal with struggling prey," said Gregory Erickson, a graduate student in biology at UC-Berkeley and lead author on the paper.
However, since hunting animals such as lions also scavenge, the jaw strength alone does not settle the argument of whether Tyrannosaurus rex was a hunter or mainly a carrion feeder.
Erickson believes that the success his group has had in measuring bite strength will cause other groups to pay attention to the significance of gnawed, fossilized bones, which often aren't found in connection with any other piece of the skeleton.
Distributed by Scripps Howard News Service