Like a Komodo dragon, the Tyrannosaurus rex needed lips to preserve its fangs, a new study says. Prior hypothesis’ believed T. rex teeth were like a crocodile’s, visible even when its jaw was ...

So researchers have often turned to crocodiles, whose exposed teeth poke directly out of the jaw with no lip-like tissue covering them. Even when a crocodile’s jaws are shut, its teeth are visible.

An American alligator may go through some 3,000 teeth in its lifetime, but the T. rex required about two years to replace just one tooth. This suggests the large dinosaurs needed lips to preserve ...

The teeth of T. rex and its two-legged, three-toed meat-eating kin—known as theropods—were likely covered by thin, scaly lips resembling those of some modern lizards, according to a study ...