Dinosaurs lived a long time ago before humans were around. Skeletons tell us what shape they were. Little is known about their daily lives. Looking at what they ate helps us to know more about them.

Researchers have found teeth marks of one dinosaur on the bones of another dinosaur. A large dinosaur know as Tyrannosaurus Rex, or T-Rex, made teeth marks on the bones of a smaller dinosaur. There were many marks on the bones suggesting that the dinosaur kept chewing on the bones.

The bones of a T-Rex were found 65 million years after they all died and became extinct. People did not know if it killed what it ate or only ate already killed animals.

Scientists found that the bite of a T-Rex was strong enough to kill another animal. This does not prove that he tracked and killed his food himself. It does show that he could use his bite to kill other animals.