Hypacrosaurus

What it was like

Hypacrosaurus was a duck-billed plant eater about 9 meters (30 feet) long. It had a rounded, hollow crest on top of its head, a little like that of its close relative Corythosaurus, and a tall ridge of spines along its back.

The hollow crest held long air passages that may have helped it make loud, low calls. Like other duckbills, it ground tough plants with rows of tightly packed teeth.

Its world

It lived in the Late Cretaceous in what is now Alberta in Canada and Montana in the United States. Its bones come from rocks such as the Horseshoe Canyon and Two Medicine formations. Predators such as Daspletosaurus shared its world, along with the smaller hunter Troodon and the ostrich-like Struthiomimus.

How it was found

Brown named Hypacrosaurus in 1913. There are 34 recorded finds, including nests, eggs and hatchlings from Montana. These babies have helped scientists study how duckbills grew up, and how their crests developed as they aged.