KRITOSAURUS (KRIT-oh-SORE-us)

Period: Late Cretaceous

Order, Suborder, Family: Ornithischia, Ornithopoda, Hadrosauridae

Location: North America (United States)

Length: 30 feet (9 meters)

Kritosaurus was a large, flat-headed duckbilled dinosaur. It had a ridge of bone between the eyes and the snout that gave it a distinguished "Roman nose" appearance. In other ways, Kritosaurus was similar to its relative Hadrosaurus. One of the largest hadrosaurs, Kritosaurus weighed up to three tons and stood around nine feet tall at the hips. The long, heavy tail gave this plant-eater balance when it walked on two legs (bipedal). Its rear feet had three large toes ending with blunt hooves like those of elephants. The front legs were small and seldom used for walking; the animal may have used them in gathering food or in preparing nests.

The skull of Kritosaurus was long and slender, with a broad, flat face that looked like the bill of a duck. The ridge of bone in front of the eyes may have increased the nasal cavity to improve its sense of smell, an unusual feature for a reptile.

Kritosaurus had hundreds of tightly packed grinding teeth for crushing the tough plants it ate. To gather food, it probably stood on its tall rear legs and used its heavy tail as the third leg of a tripod. It then could reach high into trees to gather leaves and branches.

Like other duckbills, Kritosaurus probably lived in herds and protected the young from giant predators such as Tyrannosaurus and Albertosaurus. Kritosaurus lived throughout western North America from Montana to New Mexico.