What it looked like
Deinonychus was built to kill. It was a lightly built, fast-moving, agile, bipedal (it walked on two legs), bird-like dinosaur. It had a curved, flexible neck and a big head with sharp, serrated teeth in very powerful jaws.

Each of its three fingers on each arm had large, sharp, curved claws. It had four toes on its feet; the second toe had a 13 cm long sickle-like claw to cut and slash. Its long tail had bony rods running along the spine so that it was rigid, not bendy. The tail was used for balance and fast turning ability. It had quite a large brain and large, keen, eyes.

What it ate
Deinonychus was a carnivore, a meat eater. It probably ate just about anything it could slash and tear apart. When hunting in packs, Deinonychus could probably kill any prey it desired.

How it moved around
Deinonychus walked on two slender, bird-like legs. It must have been a fast runner, considering its legs and light weight. When it ran, it turned its huge foot-claw upwards and ran on the other toes.

How it probably behaved
Deinonychus may have hunted in packs, attacking even very large animals, perhaps even large herbivores. Tenontosaurus may have been among its prey. It was an unarmored but fast dinosaur whose fossils have been found near Deinonychus fossils.

Deinonychus were among the smartest of the dinosaurs, because they had such large brains. This made them very deadly predators.