Pachyrhinosaurus was a rhinoceros-like dinosaur with horns, frill, bony ornaments and a beak.
Pachyrhinosaurus lived in Cretaceous Alaska and Alberta. With some of its range near the poles, these dinosaurs would have experienced long winters and months of darkness.
With relatively small and primitive hearing apparatus, it is likely that Pachyrhinosaurus would not have had very good hearing.
As a herbivore, Pachyrhinosaurus had strong, stubby, cheek teeth. These were packed tightly together to form a single continuous cutting surface for slicing food into small pieces, like a pair of prehistoric scissors.
Like its hearing apparatus, the olfactory centres of Pachyrhinosaurus were reduced, which means its sense of smell was poor.
In 1973 at Pipestone Creek, Alberta, Canada, science teacher Al Lakusta discovered hundreds of Pachyrhinosaurus remains. This bone bed suggests that, about 73 million years ago, a herd of juvenile and adult individuals died in a flood. The remains have given us a unique insight into the lifestyle of these animals.
Height: 2.5m (8.2ft)
Length: 7m (22.96ft)
Weight: 3 tonnes (3.36 short tons)
Top speed: 45kph (28mph)
Vision: Pachyrhinosaurus had poor vision. Palaeontologists have studied its brain cavity and found that the optic centre which controls the animal's vision was not well developed.
Skin: Pachyrhinosaurus' skull bore massive reinforced bones – called bosses – over its noses and eyes, most probably for display and head butting rival males. The animal's horns and other bony ornaments were smaller than its bosses and the arrangements differed depending on the species of Pachyrhinosaurus. The frill was also topped with a prominent pair of horns.
Brain: Pachyrhinosaurus had a small, poorly developed brain. It was not a bright animal.
Prey: Herds of Pachyrhinosaurus needed vast areas of vegetation in order to sustain their numbers. To get them through the polar months, some scientists believe they might have migrated hundreds of miles to warmer climates.
Bite: Pachyrhinosaurus used its battery of strong cheek teeth to chomp on low-lying tough fibrous plants and its sharp beak to slice vegetation.
Nest: Scientists have uncovered a nest from a Protoceratops, a relative of Pachyrhinosaurus. The nest was round in shape, measuring 0.7m (2.3ft) in diameter and containing 15 baby dinosaurs. Pachyrhinosaurus would probably have had similar nests.