English: Corythosaurus casuarius is a lambeosaurine hadrosaur from the Late Cretaceous of what is now western North America, known for the large rounded bony crest atop its skull. The complex internal structures of this crest were able to produce loud, low-pitched vocalizations for communication. Aside from the crest, its skull was fairly small compared to other hadrosaurs. Corythosaurus had a relatively short snout, ending in a narrow beak. Corythosaurus was about 9 m in length, and weighed around 3 t. Like other hadrosaurs, it was facultatively bipedal, meaning it was able to locomote either on its two hind legs, or on all fours, depending on the situation.