Parasaurolophus was a hadrosaurid (duck-billed) dinosaur from the Upper Cretaceous Period (about 76-65 million years ago) of North America. Its name means 'near crested lizard', which refers to another hadrosaurid, Saurolophus, discovered before Parasaurolophus. Parasaurolophus were about 10 m (33 ft) long, 5 m (16 ft) high and weighed around 3500 kg (7,700 lb). Like other hadrosaurs, they could alternate between two legs and four, probably preferring a quadrupedal gait while they foraged for food and assuming a bipedal mode for faster running. They were fully terrestrial animals, as evidenced by footprints.