Narrator: This is Science Today. Everyone knows Tyrannosaurus rex as the fiercest predator of the dinosaur world. But some scientists think the big dinosaur was merely a scavenger, munching food that other dinosaurs killed. By simulating a T. rex bite in the lab, biologist Greg Erickson of the University of California, Berkeley showed that, theoretically at least, its teeth were strong enough to bring down a live animal.

Erickson: I think if we want to really get at whether it was actually killing prey items we need to look at more tooth marks -- start looking for bite marks on skeletons, say, where the bites look like they've crushed the skull or penetrated the spinal cord around the neck or something like this -- the kind of bites we find the big predators today make. These are killing marks.

Narrator: As opposed to eating marks, which is what Erickson simulated.

Erickson: The problem being so far that very few people have looked for dinosaur bite marks, in fact it was once believed they were fairly rare. Our recent findings seem to suggest that actually they're quite common, we just need to start looking for them. Scientists need to start recognizing where to look for them and what they might look like.

Narrator: For Science Today, I'm Steve Tokar.