<span style="font-family:"font-size:18px;">Dr Lautenschlager said: "Theropod dinosaurs, such a or , are often depicted with widely-opened jaws, presumably to emphasise their carnivorous nature. Yet, up to now, no studies have actually focused on the relation between jaw musculature, feeding style and the maximal possible jaw gape."

Tyrannosaurus rexAllosaurus fragilisErlikosaurus andrewsiDr Lautenschlager said: "All muscles, including those used for closing and opening the jaw, can only stretch a certain amount before they tear. This considerably limits how wide an animal can open its jaws and therefore how and on what it can feed."

The study found that the carnivorous  and were capable of a wide gape (up to 90 degrees), while the herbivorous  was limited to small gape (around 45 degrees).

TyrannosaurusDr Lautenschlager said: "We know from living animals that carnivores are usually capable of larger jaw gapes than herbivores, and it is interesting to see that this also appears to be the case in theropod dinosaurs."

Royal Society Open Science