Dinosaurs

A Bite From T. Rex Was Like Being Crushed By Three Cars

Tyrannosaurus rex. The king of the dinosaurs. There may have been bigger carnivorous dinosaurs (Spinosaurus was a T. rex and a half), but the original monster still occupies the top spot in most dino lovers' hearts. A new analysis of Rexy's teeth shows that that favored position is well-deserved—she could bite down harder than any other animal back then or since.

The Strongest Bite Ever

T. rex lived at the end of the Cretaceous period, and roamed the western side of the continent now known as North America. She shared that habitat with other big-name dinosaurs such Triceratops and Ankylosaurus—you might recognize the former as the most famous horned dinosaur ever, and the latter as the one that's basically a giant ball of spikes and bone and surliness. But as well armed as those dinosaurs were, T. rex could tear into them like she was biting into a Cadbury egg. That's because her jaws could bite down with 7,800 pounds of force—the weight of three small cars—with each tooth exerting pressures of up to 431,000 pounds per square inch. It doesn't matter how well-armored you are at that point. Once those teeth are around you, it's lights out.

Paleontologists have long known that T. rex had a bite beyond all others, but only recently have they realized how badly they had been underestimating her. Previous models used cow bones to simulated the kinds of bites found on fossil bones, and estimated that T. rex could produce around 3,000 pounds of force. That's the weight of a fully grown rhinoceros, and certainly nothing to sneeze at. But the new model started by calculating the bite force of the American alligator (the reigning bite champ of the present day), then worked backwards to apply that calculation to Tyrannosaurus. The result was more than twice as powerful as the old calculation, and would shatter even the heaviest bone without an issue. That's an ability that modern-day reptiles and even larger carnivorous dinosaurs lacked, and probably reflects the particularly well-protected food sources that T. rex hunted.

Biting Off Exactly What She Could Chew

A lot of different factors played a role in the power of T. rex's jaws. First is size. At five feet long, T. rex's head was massive, and had plenty of space for incredibly powerful jaw muscles. Next is the teeth themselves. They were conical and serrated, and the biggest of them were seven inches long. That meant that not only could the puncture nearly any material, but when she loosened her grip her teeth would saw through the bone and cause even more damage. She also had a lot of them—about 50, with 30 on the top row alone (most humans have 32 total).

Of course, even the most formidable teeth can't take that kind of wear and tear forever, so each of those chompers would get a replacement every two years. The result is that T. rex likely consumed bone and marrow like modern-day hyenas do, and that's a behavior that hasn't been discovered in any other dinosaur or reptile. Guess there's a reason why we haven't uncovered any dinosaur dentists.

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Key Facts In This Video

  1. Yutyrannus huali is a newly discovered Tyrannosaur species whose fossils have been found with preserved remains of mono-filamentous feathers similar to an emu's. 00:22

  2. Starting around age 14, Tyrannosaurus Rex would gain around 2 kilos a day until the age of 18. 00:59

  3. When Steven Spielberg made Jurassic Park in 1993, there was no evidence to suggest T. Rex hunted live prey. 02:05

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Written By
Curiosity Staff
May 30, 2017