SCIENCE

New research suggests T. rex teeth were probably not protruding fangs, but kept hidden by thin, scaly lips. (Guardian)

How did tyrannosaurs use those teeth? Use our archived activity to find out.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• New research suggests Tyrannosaurus rex did not have fangs. What are fangs?
  • Fangs are simply long, sharp teeth that protrude from an animal’s mouth.
    • In some animals, such as snakes or spiders, fangs are hollow and used to inject venom. Reptiles, such as dinosaurs and crocodilians, do not have hollow fangs and use their sharp, solid teeth for biting, holding, and tearing the flesh of their prey.

• If T. rex didn’t have fangs, how did it terrorize the neighborhood?
  • It smiled. Those banana-sized teeth could still do all that damage, they were just hidden inside the dinosaur’s mouth, until it pulled back its lips.

• How did paleontologists come to the conclusion that T. rex had lips?
  • They studied the enamel of T. rex teeth. Tooth enamel is the hard, white substance that covers the visible part of teeth.

• How can tooth enamel indicate whether T. rex teeth were inside or outside its mouth?
  • Tooth enamel needs to stay hydrated to stay healthy. Water or saliva constantly washes over enamel to keep it strong and smooth.
    • “If you have your teeth sticking out, you can’t hydrate the enamel. You can’t maintain it properly.” And if tyrannosaurs are known for anything, it’s dental hygiene.

• How do toothed reptiles such as lizards or crocodilians maintain their pearly whites?
  • Well, lizards have lips. Their tiny, pointed teeth are almost always covered by their scaly skin. T. rex may have looked a lot like a monitor lizard when it had its mouth closed.
  • The crocodilians (crocodiles, alligators, caimans, and gharials) don’t need lips. They are constantly hydrating their teeth as they swim … and lurk … in the water.

TEACHERS TOOLKIT

Guardian: Tyrannosaurus rouge: lips may have hidden T rex’s fierce teeth

Nat Geo: Dinosaur Bodies