New Mexico Museum of Natural History and Science

Parasaurolophus is one of the largest hadrosaurs and had the largest crest on its skull of any hadrosaur.

Popularly known as the duck-billed dinosaurs, hadrosaurs were among the most common and successful plant-eating dinosaurs of the Cretaceous. Some of the hadrosaurs had hollow tubes or crests on their skulls that may have served as visual display and probably acted as resonators to produce distinctive calls.