Deinonychosaurs were relatively small - ranging from about 6 ft.(1.8m) to 15 ft.(4m) in length. These raptors were fast and agile, running on their powerful hind legs and using their long, stiff tail to keep balance and to help change directions quickly.

Deinonychus was highly specialized for swift movement and savage attack. With its terrible claw flicked forward it slashed its prey with one foot while standing on the other. This kind of behavior required good coordination, excellent eyesight and a high level of energy.  By hunting in packs Deinonychus may have brought down prey much larger than itself.