Eoraptor was one of the earliest dinosaurs. Its name means “dawn thief ” in recognition of its place at the dawn of the dinosaur era. About the size of a fox, Eoraptor stood and ran quickly on its two hind legs. It killed prey by using its claws and teeth to tear the victim apart.
■ When: 230–225 million years ago (Middle Triassic)
■ Fossil location: Argentina
■ Habitat: River valleys
■ Length: 3 ft (1 m)
■ Diet: Lizards, small reptiles, sometimes plants
Only one complete fossil skeleton of Eoraptor has been found so far, but it reveals much about early dinosaurs. Eoraptor had primitive features, including five fingers on its front limbs, weak claws, and lizardlike hips. Scientists are not sure whether it had scales or feathers. Eoraptor is thought to have been a fierce and quick-witted hunter. The mouth was full of sawlike teeth, ideal for slicing through flesh. Some scientists think Eoraptor may have eaten plants too.
The first Eoraptor fossils were discovered in 1991 in the Valley of the Moon, a region in northwestern Argentina. It is a barren landscape of bare rock, and looks like the surface of the Moon. When Eoraptor lived there in the Late Triassic the area was a lush river valley.
Because Eoraptor’s eyes were set on the side of its head, it couldn’t see straight ahead well, but it did have a good allaround view.
Eoraptor had the bladelike teeth of a carnivore—suitable for slicing through meat. It mainly hunted small animals, but may have taken on bigger prey by tearing out lumps of flesh and waiting for its victim to weaken.