Deinonychus is a genus of maniraptoran dinosaurs similar in appearance to Velociraptor, though larger in size, though not as large as Utahraptor.

This 3.4 meter (11 ft) long dinosaur lived during the Early Cretaceous, about 115-108 million years ago. Fossils have been recovered from the U.S. states of Montana, Wyoming, and Oklahoma.

They had a large claw on each foot that they could use to attack their prey. Scientists think they may have hunted in packs, like lions and wolves. It's tail contained ligaments and tendons that could keep the tail stiff so it could use it as a counterbalance. Due to their leg muscles and structure they could be said to be good at jumping and running.


Paleontologist John Ostrom's study of Deinonychus in the late 1960s started the debate on whether dinosaurs were warm-blooded.[1] It is now accepted that all or most smaller theropods had feathers whose function was temperature regulation.

Dc card deino big

Deinonychus, as it was commonly depicted in the late 1990's and early 2000's

Ostrom noted the small body, sleek, horizontal, posture, and—especially—the enlarged claws on the feet, which suggested an active, agile predator.[2] Before this, the popular idea of dinosaurs had been one of plodding, reptilian giants.[3][4]

'Deinonychus' means 'Terrible claw'. This refers to the large, sickle-shaped claw bone on the second toe of each hind foot. In life, archosaurs have a horny sheath over this bone which extends the length. Ostrom reconstructed the claw as over 4.7 in long.[2]

The species name antirrhopus means “counter balance”, which refers to Ostrom's idea about the function of the tail. As in other dromaeosaurids, the tail vertebrae have a series of ossified (bony) tendons and super-long bone processes. These features seemed to make the tail into a stiff counterbalance.

A fossil of the very closely related Velociraptor mongoliensis has an articulated tail skeleton that is curved laterally in a long S–shape. This suggests that, in life, the tail could swish to the sides with some flexibility.[5]

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 in The Land Before Time

In the movies they are called Sharpteeth , but they may be called Fast Biters like their relatives. To date, the only film in which Deinonychus are depicted is The Land Before Time VII: The Stone of Cold Fire, where, in a flashback sequence, six individuals are seen attacking the herd that Pterano lead, during the events of the original film. It's not possible that most of the herd made it out of the ambush alive, although some could have escaped since some of the herd had weaponry to protect themselves.



  1. Desmond A.J. 1977. The hot-blooded dinosaurs. ISBN 0-8600-7494-3
  2. 2.0 2.1 Ostrom, J. H. (1970). "Stratigraphy and paleontology of the Cloverly Formation(Early Cretaceous) of the Bighorn Basin area, Wyoming and Montana". Bulletin of the Peabody Museum of Natural History 35: 1–234. 
  3. Bakker, Robert T. 1975. Dinosaur Renaissance, in Scientific American, April issue.
  4. Bakker, Robert T. 1986. The Dinosaur heresies: new theories unlocking the mystery of the dinosaurs and their extinction. Zebra Books.
  5. Norell, Mark A.; & Makovicky, Peter J. (1999). "Important features of the dromaeosaurid skeleton II: information from newly collected specimens of Velociraptor mongoliensis". American Museum Novitates 3282: 1–45.