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.

Deinonychus ewilloughby

Modern depiction of Deinonychus

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

Deinonychus are commonplace in entries of The Land Before Time series released after the turn of the century, first appearing in 2000's The Land Before Time VII: The Stone of Cold Fire and making common appearances afterwards. They are incorrectly portrayed as having two hand claws, instead of three, and, as with almost all of the other dromaeosaurs in the series, they are depicted without any sort of plumage.

In their debut in a flashback sequence in The Stone of Cold Fire, three 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.

Compared to the raptors that appear later on in the series, the ones that appear in VII, though still physically identical to its succesors, are somewhat unique for their species, being light gray with orange eyes and dark patches on their faces; Deinonychus that appear later in the series, however, come in a variety of bright colors, and have eyes that are usually either red or yellow.

In 2005's The Land Before Time XI: Invasion of the Tinysauruses, a pair of Deinonychus appear as threats during the film's climax. They chase the Tinysauruses through a cavern. Then the Tinysauruses hide in a rock pile and lose the raptors, which were heading for the Great Valley. When they reach the valley, they are first encountered by Littlefoot's friends, who are looking for him as they are apologizing for being mean to him.

The Deinonychus attack them and Littlefoot. As one goes after Cera, Tria saves her. Then Ducky is chased by the purple one and got hit by a branch swung by Littlefoot from behind a tree. The blue Deinonychus chases Spike & Petrie and first got pecked in the face and tickled by Lizzie and Skitter. The purple Deinonychus chases the others and confronted by his ability to strike by Tria plus Daddy Topps who showed up with bravery and courage and it got thrown off into the air. The blue one continues biting on Lizzie and Skitter but accidentally bit on the tail instead. Then the Tinysauruses jump on them, but are then thrown off. Daddy Topps confronts the Deinonychus, and then every member in the Great Valley comes and chases them away.

Outside of the films, Deinonychus is commonly portrayed in the television series; Screech and Thud in particular act as the secondary antagonists of the series, and as the subordinates of Red Claw. A trio of Deinonychus also appear in The Lonely Journey, and a mother Deinonychus appears in "The Great Egg Adventure".

Deinonychus are last seen in The Land Before Time XIII: The Wisdom of Friends, where an entire pack was being chased by a Tyrannosaurus.


  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. 
Community content is available under CC-BY-SA unless otherwise noted.