SciNews has a story about Tyrannosaurus rex.  A recent study looked the bite force of juvenile T. rex and found they had a bite force somewhere between modern hyenas and crocodiles at about 5,641 newtons.  Humans deliver a force less than 1/10 at around 300 newtons. Details of the story can be found in a paper in PeerJ by researchers at the University of Wisconsin Oshkosh.

For the study, University of Wisconsin Oshkosh’s Professor Joseph Peterson and colleagues made a replica of the scimitar-shaped tooth of a young Tyrannosaurus rex using a dental-grade cobalt chromium alloy.

They then mounted the metal tooth in a mechanical testing frame and pushed it slowly, at a millimeter per second, into a fresh-frozen and thawed humerus of a cow.

Forces required to replicate punctures were recorded and puncture dimensions were measured.

“What we did, an actualistic study, is to say, Let’s actually stab the thing with a tooth and see what it does,” Professor Peterson said.

“What we are finding is that our estimates are slightly different than other models, but they are within a close enough range — we are on the same page.”

The paleontologists determined that juvenile Tyrannosaurus rexes could have exerted up to 5,641 newtons of force, somewhere between the jaw forces exerted by a hyena and a crocodile.

Compare that to the bite force of an adult Tyrannosaurus rex — about 35,000 newtons — or to the puny biting power of humans: 300 newtons.

Previous bite force estimates for juvenile Tyrannosaurus rexes — based on reconstruction of the jaw muscles or from mathematically scaling down the bite force of adult Tyrannosaurus rexes — were considerably less, about 4,000 newtons.

“If you are up to almost 6,000 newtons of bite force, that places them in a slightly different weight class,” Dr. Tseng said.