Saurolophus was a large, herbivorous dinosaur that lived during the Late Cretaceous period, around 76 to 73 million years ago. It belonged to the group of dinosaurs known as hadrosaurs, or duck-billed dinosaurs, and was characterized by its long, backward-curving crest on its head. This crest may have been used for communication or display purposes. Fossils of Saurolophus have been found primarily in North America, particularly in what is now Canada and the United States. It could grow up to 30 feet long and walked on both two legs and four, allowing it to adapt to different environments while foraging for plants.