Deinonychus << dy NON ih kuhs >> was a small, meat-eating dinosaur. Deinonychus lived about 110 million to 100 million years ago, during the Cretaceous Period. It grew about 9 feet (2.7 meters) long, stood about 5 feet (1.5 meters) tall, and weighed approximately 150 pounds (70 kilograms). Deinonychus walked and ran on two hind legs, using its long, stiff tail for balance.
Deinonychus was a kind of theropod dinosaur. This diverse group includes all dinosaurs that are known to have been predators (hunters). Deinonychus had a body well suited for hunting. The animal’s head had large eyes, powerful jaws, and sharp serrated (saw-edged) teeth. Its teeth curved backward and could easily chew up prey. The dinosaur also had elongated arms and long, slender fingers to grasp its victims. On each foot grew a long bladelike claw, which Deinonychus used to tear prey apart. These claws measured about 5 inches (12.5 centimeters) in length. They give the dinosaur its name, which means terrible claw. Deinonychus probably hunted in packs to kill larger animals.
Fossils of Deinonychus were first discovered in 1931. Fossils of this dinosaur are found at sites in Colorado, Maryland, and Wyoming. In the 1960’s, paleontologists observed that the bones of Deinonychus were similar in many ways to the bones of modern birds. Today, abundant fossil evidence suggests that feathers originated among theropod dinosaurs, before the appearance of birds. Scientists now also understand that many theropod dinosaurs, including Deinonychus, had feathers. Most scientists regard birds as living descendants of theropod dinosaurs.
