Hadrosaurs were herbivorous dinosaurs, members of the family Hadrosauridae, which lived mainly during the Cretaceous period, approximately 143–66 million years ago. They were large dinosaurs that could walk on either two or four legs, traveled in herds, and ate vegetation. Among the famous features of Hadrosaurs are their duck-billed snouts, as well as the possible hollow or solid crests on their heads, probably used for visual and auditory display in social contexts.
Their teeth were used to grind plants and were arranged in multiple rows that were replaced when old teeth began to wear down. Among the best-known genera of Hadrosaurs are: Edmontosaurus and Parasaurolophus.
