Edmontosaurus and other duck-billed dinosaurs, or hadrosaurs, were very common in the Northern Hemisphere during the Late Cretaceous Period. Some species of duck-billed dinosaurs moved about in herds numbering hundreds or thousands of individuals.

When first discovered, hadrosaurs were thought to be water dwellers. Later study showed that while the body is built for land, the broad tail enabled these animals to move very easily through water. The paddle-like hands of Edmontosaurus support this observation.

The snout of Edmontosaurus ended in a large, broad beak suitable for cropping vegetation. Up to 2,000 tightly packed teeth at the back of the jaws were used for chewing and grinding tough plant material.