Deinonychus is a dinosaur which lived about 115 million years ago during the Cretaceous Period. Its name means "terrible claw," and it was given this name because of the large, retractable hunting claw on each of its feet. Deinonychus could reach a hip height of 3 feet, a length of 12 feet and a weight of approximately 150-160 pounds. It was quick and agile, probably lived in small packs, and some studies suggest that Deinonychus had the biggest brain (in relation to its body) of all theropods and therefore was very intelligent - they probably hunted their prey with a certain level of organization. Like Velociraptor dinosaur, they had all the tools they needed to be aggressive predators.It used this claw to tear into the flesh of the dinosaurs it hunted. The claw would snap forward and make a large, deep wound when it attacked. The similarity of this dinosaur to a bird caused scientists to believe that these dinosaurs actually did have feathers like modern birds. Although there is no solid proof that Deinonychus had feathers, the finding of Velociraptor feathers may be enough proof to postulate that these dinosaurs also had feathers. Some scientists have postulated that these dinosaurs probably preyed on Tenontosaurus as a food source. For example, Tenontosaurus weighed over 2 tons, and this dinosaur only weighed 160 pounds. Which means, that if they did indeed hunt these animals, then they would have had to have done it in packs. It was first discovered in 1931 near the town of Billings, Montana by Barnum Brown. Since then, fossils have been found in parts of Wyoming and Oklahoma as well. Deinonychus is probably the best known of the dromeasaurids as nine specimens have been discovered A skeleton of Deinonychus can be seen on display at the American Museum of Natural History or the Harvard Museum of Comparative Zoology.