Deinonychus

Deinonychus (dī'nənī`kəs) [Gr.,=terrible claw], swift bipedal carnivorous dinosaur of the early Cretaceous period, approximately 119–93 million years ago. Fossil specimens have been discovered in Montana and Wyoming. Adults were around 10 ft (2.5 m) from head to tail and 1 ft (3 m) high. The second toe of each three-toed foot was modified into a long sickle-shaped claw, and the hands, each finger of which also ended in a claw, were adapted to grabbing prey. Deinonychus is thought to have been a very fast-moving predator. It belongs to the group of saurischian theropods [Gr., = beast feet] that includes Tyrannosaurus, Velociraptor, and living birds.

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Deinonychus

Genus of clawed theropod dinosaurs that flourished in western North America during the Early Cretaceous period (144–99 million years ago). Deinonychus walked and ran on two legs, yet its killing devices, large sickle-like talons 5 in. (13 cm) long on the second toe of each foot, required it to stand on one foot while slashing at its prey with the other. Its long, outstretched tail was enclosed in bundles of bony rods that grew out of the tail vertebrae, making it very rigid. About 8–13 ft (2.4–4 m) long and weighing 100–150 lbs (45–68 kg), it had a large brain and was evidently a fast, agile predator.