Deinonychus Characteristics

Deinonychus measured around 10 feet (3 metres) in length, 5 feet (1.5 metres) in height and weighed up to 175 pounds (80 kilograms). This dinosaur was around 4 feet (1.2 metres) tall at the shoulder. Its femur (thigh bone) was 31 centimetres long and it had a maximum skull length of 16.4 inches. Studies of the skull have progressed a great deal over the decades. Ostrom reconstructed the partial, imperfectly preserved skulls that he had as triangular, broad and quite similar to the Allosaurus. The skull of Deinonychus was different from that of the Velociraptor in that it had a more robust skull roof like that of Dromaeosaurus and did not have the depressed nasals of Velociraptor. Both the skull and the lower jaw had fenestrae (skull openings) which reduced the weight of the skull.

Deinonychus was a lightly built, fast-moving, agile, bipedal (walked on two legs), bird-like dinosaur. It was built to kill. This meat-eater had a curved, flexible neck and a large head with sharp, serrated teeth in very powerful jaws. Each of its 3 fingers on each hand had large, sharp, curved claws. It had 4 toes on each foot, the second toe had a 5 inch (13 centimetre) sickle-like claw, and the other toes had smaller claws. Its long tail had bony rods running along the spine, giving it rigidity. Its tail was used for balance and fast turning ability. Deinonychus had a relatively large brain and large, keen eyesight.

Deinonychus was a carnivore, a meat eater. Deinonychus may have hunted in packs, attacking even very large dinosaurs, perhaps even large sauropods and ankylosaurids. Deinonychus, along with the other dromaeosaurids, were among the smartest of the dinosaurs, as calculated from their brain:body weight ratio. This made them very deadly predators. Deinonychus remains have been found closely associated with those of the ornithopod Tenontosaurus. Teeth discovered associated with Tenontosaurus specimens imply it was hunted or at least scavenged upon by Deinonychus. Deinonychus must have been one of the most terrifying animals to live in the Cretaceous period.

Deinonychus walked on two slender, bird-like legs. It was most probably a very fast runner, considering its legs and light weight. When it ran, it rotated its huge foot-claw upwards and ran on the other toes.

Deinonychus was first found by Grant E. Meyer and John H. Ostrom in southern Montana (in the western United States) in 1964. Deinonychus antirrhopus was named by Ostrum in 1969. More than eight Deinonychus fossils have been found in Montana, Utah, and Wyoming, USA.