Tyrannosaurus rex had the most powerful bite of any terrestrial animal — modern or prehistoric.
The force of T. rex's bite was comparable to having an elephant sit on the victim with each crunch, according to a paper in the latest issue of Biology Letters. The carnivorous dinosaur’s biting force was between 35,000 to 57,000 newtons at a single tooth.
In comparison, human biting force is usually documented as being less than 1,000 newtons, suggesting that T. rex could have bitten through thick bone and probably whatever else it wanted to attack.
“I have no idea what the bite would do to an animal beyond hurt a lot,” co-author Karl Bates told Discovery News. “The force is obviously much higher than alligators and lions (some of the most forceful living animals), and you wouldn’t want to be bitten by either of those.”
Bates, a researcher in the University of Liverpool’s Department of Musculoskeletal Biology, and colleague Peter Falkingham of the University of Manchester artificially scaled up the skulls of a human, an alligator, a juvenile T. rex and an Allosaurus to the size of an adult T. rex. In each case, the bite forces increases as expected, but they did not increase to the level of the adult T. rex, suggesting that this formidable predator had the most powerful bite of any land animal.
Perhaps the only contender would be Gigantosaurus, another huge carnivorous dinosaur, but its bite force hasn't been measured yet.
Alligators hold the record for highest bite force of a living terrestrial animal, but Falkingham said he’s not sure how they would compare to great white sharks. Larger crocodilians, such as Nile crocs, have not been measured, but they would still not exceed the biting force of T. rex.
Previous studies estimated that T. rex bit at a force between 8,000 and 13,400 newtons, but this latest study tested a range of muscle powers, as it is not precisely known what the muscles of dinosaurs were like, since this tissue has not survived. The researchers believe their new numbers better match the size and body structure of T. rex a dinosaur thought to weigh more than 13,228 pounds.
“We speculate in our paper that the high bite force of adult T. rex may be indicative of it being a ‘large prey specialist,’” Falkingham told Discovery News. He and Bates explained that the carnivore preyed upon various plant-eating dinosaurs, as evidenced by T. rex tooth marks found on bones for some of these large beasts.
The scientists further determined that juvenile T. rex had a relatively weaker bite than the adult T. rex, even when size differences and uncertainties about muscle size were taken into account. This indicates the species underwent a change of feeding behavior as it grew.
“It certainly makes sense from a ‘survival of the fittest’ point of view for members of the same species to avoid competition with themselves,” Bates said.
John Hutchinson, a professor of evolutionary biomechanics at the University of London’s Royal Veterinary College, told Discovery News “there’s no question that T. rex had a remarkably strong bite — that’s old news — but this study suggests it had an even stronger bite than previously thought.”
Hutchinson said the study utilized “a very sophisticated computer analysis.” He also agrees that the ecology of Tyrannosaurus changed dramatically during the dinosaur’s growth, which involved going from just 13 pounds to over 13,000 in less than 20 years. He said, “Once again, we see the power of the fossil record, and computer tools, in revealing amazing animals that are so unlike creatures today.”
Stephen Brusatte, a Columbia University paleontologist who is also a researcher at the American Museum of Natural History, agrees with the new study’s conclusions as well.
“The finding that T. rex had a remarkably strong bite force, on the order of magnitude of tens of thousands of newtons, really drives home how powerful this iconic dinosaur would have been,” he commented.
Brusatte thinks the most important part of the study is the analysis on differences between the juvenile and adult T. rex.
“Juveniles were probably better suited for feeding on smaller prey," he said, "whereas adults were true killing machines adapted to use bone-crunching bites to feed on some of the largest dinosaurian prey species.”