Tyrannosaurus rex and at least one other carnivorous dinosaur were capable of opening their jaws up to 90 degrees.
Plant-eating dinosaurs, on the other hand, were limited to a narrower jaw gape, suggesting that feeding style and diet of dinosaurs were closely linked to how wide they could open their mouths.
“Theropod (carnivorous) dinosaurs, such as Tyrannosaurus rex or Allosaurus, are often depicted with widely-opened jaws, presumably to emphasize their carnivorous nature,” author Stephan Lautenschlager from the University of Bristol’s School of Earth Sciences said in a press release.
“Yet, up to now,” he continued, “no studies have actually focused on the relation between jaw musculature, feeding style and the maximal possible jaw gape.”
Of course, moviegoers have known all about this for 20 years already.