Deinonychus (a word made from combining two greek words meaning "terrible claw" pronounced "die-non-eh-kuss") was a remarkable species of carnivorous (meat-eating) dinosaur. Deinonychus was fast and vicious but fairly small in stature. It measured about three and a half feet tall, and about nine feet long. Its weight is estimated at 150 pounds.

Deinonychus hunted in a group, called a pack. Members of a pack could have killed and eaten dinosaurs much larger than themselves. In fact, the bones of several individuals of Deinonychus have been found with the skeleton of a large plant eating dinosaur, called Tenontosaurus.