Originally, this dinosaur had seven known subspecies. All of them were studied extensively in 1975 by Peter Dodson, who studied the differences between the skulls and the crests of different types of dinosaurs. He found that differences in size and shape of the seven named subspecies were actually different age groups of the same species. Today, only one species is known (C. casuarius).
Corythosaurus was about 35 feet in length from nose to tail and weighed about 4 tons. Like all hadrosaurs, it had a toothless beak. The back of the jaws, however, had a dental battery composed of hundreds of small, interlocking teeth. These teeth were used to crush and grind plant food. The teeth were continually replaced throughout the life of the dinosaur. There was a tall bony crest atop its skull, which contained the nasal passages. The nasal passages first entered the crest into separate pockets on the sides, then into a single central chamber before heading on to the respiratory system. Vocalizations would have carried through these chambers, and perhaps would have been amplified. It is thought that the sound of the Corythosaurus was a loud, low pitched cry, like that of a brass or wind instrument.
Scientists once thought that this dinosaur lived near water mostly, because of the appearance of webbed hands and feet. It was later discovered that the so-called “webs” were actually deflated padding, something like those found on many modern mammals.