The strongest bite force on Earth today belongs to the biggest reptile on the planet. The massive saltwater crocodile — which grows to 17 feet and can weigh more than ton — that lives on the coasts of southeast Asia and northern Australia chomps down with a bite measured at around 3,700 pounds of force.
Those crocs are remarkably similar to their prehistoric ancestors, which lived more than 85 million years ago. But if we go back into prehistory to the end of the Cretaceous period, we find a predator that could bite down with more than double that amount of crushing force: Tyrannosaurus rex.
In a study newly published in the journal Scientific Reports, researchers report that T. rex was capable of biting down with almost 8,000 pounds of force, with parts of certain teeth delivering a shocking 431,000 pounds per square inch of pressure. That bite force gave T. rex its ability to practice what the researchers describe as "extreme osteophagy," or extreme bone eating.
The well-known dinosaurs "stand out for habitually biting deeply into bones, pulverizing and digesting them," the authors write in the study. The ability to eat bones allowed them to get the most nutrition possible out of bones, but it's a feat that's surprising to find in animals with a reptilian sort of mouth. Normally only mammals like grey wolves and hyenas can pulverize bone in that way, though they rely on elements of tooth structure instead of pure force.
Scientific Reports, 2017
"Having high bite force doesn't necessarily mean an animal can puncture hide or pulverize bone — tooth pressure is the biomechanically more relevant parameter," paleobiologist Gregory Erickson says in a press release emailed to Business Insider. "It is like assuming a 600 horsepower engine guarantees speed. In a Ferrari, sure, but not for a dump truck."
In the case of the T. rex, Erickson and lead study author Paul Gignac found that with the powerful bite force, tooth pressure, and repetitive bites to the same area (documented in fossil records), the dinosaurs could crush and shatter bones like mammals do now.
To figure that out, the researchers generated a model of the T. rex bite relying on the fossil records and their data from analyzing crocodilian bites and using elements of crocodilian and bird (modern dinosaur) physiology.
In a way, the results were a surprise, with the overall force estimates being lower than other researchers previously predicted, according to the study. Still, their model explained the dinosaurs' prodigious bone-eating capacity — there was enough force to get the job done. The dinosaurs also had a stomach pH of less than 1.5, allowing them to digest bones.
"It was this bone-crunching acumen that helped T. rex to more fully exploit the carcasses of large horned-dinosaurs and duck-billed hadrosaurids whose bones, rich in mineral salts and marrow, were unavailable to smaller, less equipped carnivorous dinosaurs," Gignac said in the emailed press release.