Hypacrosaurus

Hypacrosaurus was a genus of duck-billed dinosaur from Alberta, Canada, and Montana, USA, in the late Cretaceous. The name means "near the tallest lizard" in reference to the fact that it was nearly but not quite as large as Tyrannosaurus (the "tyrant king lizard"). In 1913, Hypacrosaurus was described by paleontologist Barnum Brown of the American Museum of Natural History (New York). The remains were found in the Upper Cretaceous of Alberta, Canada, and in Montana. 

It was a large hollow-crested, plant-eating, duck-billed dinosaur known as Corythosaurus. On the top of its long head was a hollow helmet-shaped bony ridge flattened on the sides like the Corythosaurus ridge but thicker. Some hadrosaurs had ridges on top, it was of many different shapes; some were solid, but most were hollow. The crest was used to emit sounds, as a cooling device, courtship displays, and sense of smell enhancer. Males were identified as having larger crests than females. It had a toothless beak and hundreds of cheek teeth to grind the tough plant material it ate. It walked on two legs, a relatively fast dinosaur, and its long, heavy tail for balance. However, it had no natural defenses of its own. It was a herbivore that ate pine needles, seeds, fruits, twigs and magnolia leaves.

It lived in humid forests and had been a grazing animal. Like some dinosaurs, it laid eggs and was probably covered with sand and plant material. It is estimated that the Hypacrosaurus was about 9.1 meters long and weighed up to 4.0 tons.