Dienoycus facts for kids

Deinonychus (say: Dye-NON-ih-kus) was a type of dinosaur that lived a long, long time ago. It was a meat-eating dinosaur, known as a theropod, and belonged to a group called dromaeosaurids. There's only one known species in this group: Deinonychus antirrhopus.

What did Deinonychus look like?

This dinosaur could grow up to 3.4 meters (about 11 feet) long. That's about the length of a small car! It lived during the early Cretaceous Period, which was around 115 to 108 million years ago.

Fossils of Deinonychus have been found in places like Montana, Utah, Wyoming, and Oklahoma in the United States. One of its most famous features was a very large, curved claw on each of its feet.

How Deinonychus changed our minds about dinosaurs

In the late 1960s, a scientist named John Ostrom studied Deinonychus. His work completely changed how people thought about dinosaurs! Before this, most people imagined dinosaurs as big, slow, and clumsy, like modern reptiles.

Ostrom showed that Deinonychus was different. It had a small body and could stand in a sleek, horizontal way. Its spine was similar to those of flightless birds, like ostriches. And of course, it had those huge claws on its feet.

All these features suggested that Deinonychus was probably very fast and a skilled hunter. This idea sparked a "dinosaur renaissance," making scientists wonder if dinosaurs were warm-blooded or cold-blooded, just like animals today.

What does its name mean?

The name "Deinonychus" means "terrible claw." This name perfectly describes the dinosaur because of the unusually large, curved claw on the second toe of each of its back feet.

This "terrible claw" was like a sickle. When scientists found the fossil, they saw that the bone for this claw was over 120 millimeters (about 4.7 inches) long. In real life, dinosaurs had a tough, horn-like covering over this bone, making the claw even longer and sharper!

The second part of its name, antirrhopus, means "counter balance." This refers to how its tail worked. Like other dinosaurs in its group, Deinonychus had a stiff tail with special bones and tendons. Scientists first thought this tail acted like a rigid counter-balance, helping it stay stable. However, later fossil discoveries of its close relative, Velociraptor, showed that the tail could actually bend quite a bit from side to side, making it very flexible.

Scientists have also found Deinonychus remains near those of another dinosaur called Tenontosaurus. This suggests that Deinonychus might have hunted Tenontosaurus, or at least eaten its remains.

How Deinonychus was discovered

The first remains of Deinonychus were found in 1931 in southern Montana. A team led by paleontologist Barnum Brown was mostly digging up a plant-eating dinosaur called Tenontosaurus. But Brown also found bones of a smaller meat-eating dinosaur nearby.

He called this new dinosaur "Daptosaurus agilis" at first. He planned to study it more, but he never finished the work. Later, another scientist, John Ostrom, looked at these old fossils. He realized that some teeth Brown found belonged to Deinonychus, but the skeleton was from a different, smaller dinosaur, which Ostrom named Microvenator.