Deinonychus facts for kids
Temporal range: Lower Cretaceous
|Deinonychus skeleton at the Field Museum, Chicago.|
Deinonychus has been described as the single most important discovery of dinosaur paleontology in the mid 20th century.
Paleontologist John Ostrom's study of Deinonychus in the late 1960s started the debate on whether dinosaurs were warm-blooded. It is now accepted that all or most smaller theropods had feathers whose function was temperature regulation.
Ostrom noted the small body, sleek, horizontal, posture, and—especially—the enlarged claws on the feet, which suggested an active, agile predator. Before this, the popular idea of dinosaurs had been one of plodding, reptilian giants.
'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 120 millimetres (4.7 in) long.
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 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.
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.
Images for kids
Artist's interpretation of a Deinonychus preying on a Zephyrosaurus in manner suggested by Fowler et al (2011)
Deinonychus Facts for Kids. Kiddle Encyclopedia.