T. rex’s incredible biting force came from its stiff lower jaw

A small bone in the mandible helped brace an otherwise flexible joint

head of T. rex fossil

The jaws of a T. rex, such as this one displayed at the Natural History Museum of Leiden, could generate bone-crushing forces thanks to a particular bone near the rear of its mandible.

Dean Mouhtaropoulos/Getty Images Plus

The fearsome Tyrannosaurus rex could generate tremendous bone-crushing bite forces thanks to a stiff lower jaw.