An adult Tyrannosaurus rex could absolutely pulverize bones. Exerting about 35,000 newtons of force, the bite of a Big Daddy or Mommy rex helped the terrifying beasts access nutrients locked away in the skeleton of downed prey. But what about the juveniles?
A study published this week in the journal PeerJ suggests that teen T. rexes had powerful jaws, but they couldn't quite crush bones like their parents. Still, they were no joke, with a bite that exerted over 5,600 newtons of force -- a little more powerful than that of a full-grown lion or tiger.
The research utilized fossils excavated in eastern Montana, at the Hell Creek Formation, which features an abundance of Triceratops and Tyrannosaurus fossils, in addition to a trove of fossilized Edmontosaurus, a duck-billed herbivore from the late Cretaceous period. One particular fossil was key to the study: the skull of a juvenile T. rex with a bite mark across its face.
The team believes this was a case of intra-species warfare. "What, other than another T. rex, would be able to chomp another T. rex and puncture its skull?" said Joseph Peterson, a paleontologist who studies fossil injuries at the University of Wisconsin in Oshkosh.
Based on the deformations in the bone, Jack Tseng, assistant curator in the University of California Museum of Paleontology, created a replica T. rex tooth with an alloy, slowly pushing it into a thawed cow bone to see how much pressure was required for it to crack. It's a valuable proxy for a real T. rex bite, but Tseng notes there's no one number that perfectly describes an animal's bite forces -- it comes down to technique.
It does provide helpful information, though. Understanding the strength of a juvenile T. rex's bite helps show the creature's bite strength got stronger over time.
"This actually gives us a little bit of a metric to help us gauge how quickly the bite force is changing from juvenile to adulthood, and something to compare with how the body is changing during that same period of time," Peterson said. "It is just adding more to that full picture of how animals like tyrannosaurs lived and grew and the roles that they played in that ecosystem."
With a bite force comparable to the big cats, it seems like a tiger versus T. rex matchup would have been a titanic struggle. Of course, that pesky asteroid that ended the age of the dinosaurs means we'll never know.