Pachycephalosaurus Facts
| Diet | Herbivore |
| Height | 2m |
| Length | 4.5m |
| Weight | 410 kg |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Pachycephalosaur |
| Location | North America |

| Diet | Herbivore |
| Height | 2m |
| Length | 4.5m |
| Weight | 410 kg |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Pachycephalosaur |
| Location | North America |
Pachycephalosaurus was a remarkable pachycephalosaur dinosaur that lived during the final years of the Late Cretaceous period, around 72 to 66 million years ago. This distinctive herbivore roamed the forests and plains of western North America, with fossil remains discovered in Montana, South Dakota, Wyoming, and Alberta. At 4.5 metres long and weighing between 370-450 kilograms, it was the largest known member of the pachycephalosaur group.
The most striking feature of Pachycephalosaurus was its incredibly thick skull roof, which could reach up to 25 centimetres thick in some specimens. This massive bone dome was surrounded by small spikes and knobs, giving the dinosaur a fearsome appearance. Despite its intimidating skull, Pachycephalosaurus was entirely herbivorous, using its small, sharp teeth to slice through leaves, fruits, and other plant material.
As a bipedal dinosaur, Pachycephalosaurus walked upright on its powerful hind legs, with shorter arms ending in grasping hands. Its long tail helped provide balance whilst moving through its forest habitat. The purpose of its thick skull has been debated by scientists, with theories ranging from head-butting contests between males to simply being a display feature for attracting mates.
Pachycephalosaurus lived right up until the end of the dinosaur age, making it one of the last non-avian dinosaurs to walk the Earth before the mass extinction event 66 million years ago.
Pachycephalosaurus is instantly recognisable by its enormously thick, dome-shaped skull roof surrounded by small spikes and bumps. This bone dome could be up to 25 centimetres thick, making it one of the most distinctive skull features of any dinosaur.
Pachycephalosaurus likely lived in small herds, browsing on low-growing plants and shrubs in forested environments. The thick skull dome may have been used in ritualistic head-butting contests between rival males, though some scientists suggest it was primarily for display purposes rather than combat.
Pachycephalosaurus has appeared in several dinosaur documentaries and the Jurassic Park franchise, often depicted using its thick skull for head-butting behaviour.
Pachycephalosaurus was first described by Barnum Brown and Erich Schlaikjer in 1943. The original fossils were discovered at Montana, USA.