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Deinonychus was a predatory dinosaur with a pair of sickle-shaped slashing claws on its toes. Its name is derived from the Greek words deinos and nychus, meaning "Terrible Claw." It lived approximately 100 million years ago, in what is now Montana, in the United States.
How it lived
Palaeontological evidence show us a lot about the way this reptile lived. It probably hunted in packs with hierarchical order, because Deinonychus skeletons have been found in groups. This way they could tackle much larger prey. Teeth of Deinonychus are found with the herbivorous dinosaur Tenontosaurus, indicating that it fed on them.
Description
Deinonychus had bony rods in its tail, which could lock together at its will. This helped it to steer at high speeds and to balance its large skull.
The skull of a Deinonychus was very big compared to its body. It had large eyesockets, which probably provided it with eagle sight. Its brain to body mass ratio was around 5.5. This meant that it was extremely smart (for example, Brachiosaurus brain mass to body mass ratio was around 0.2). Its mouth contained 70 sharp, inward-curving teeth, and it had muscles adept at closing its mouth with tremendous force. It had strong and long arms compared to other theropods (like Tyrannosaurus rex), which it probably used to hang on to its prey and slash at it with its wickedly curved claw.
Deinonychus was built for speed. It had an aerodynamic body with a hollow skeleton (like birds still do today). From looking at muscle fastenings and fossilised bone structure, paleontologists believe that it had extremely developed muscles in the leg area, allowing Deinonychus to run at speeds of around 60 km/hr (35 mph).
- Skull length: 410 mm (16 in)
- Total length: 3 m (10 ft)
- Hip height: 1.2 m (4 ft)
- Weight: 80 kg (175 lb)
Discovery
Several hundred Deinonychus bones were discovered by John Ostrom and Grant E. Meyer in 1964 in southern Montana. Similarities seen between the skeleton of Deinonychus and the early bird Archaeopteryx led John Ostrom to revive the hypothesis that birds evolved from dinosaurs. Recent evidence shows that Deinonychus might even have had feathers, but it lived too late to have been ancestral to birds.
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