Dinosaurs · Pachycephalosaur
Pachycephalosaurus
Say it pack-ee-KEF-ah-lo-sore-us. The name means ‘thick-headed lizard’.
- Length
- 3 m
- Weight
- 450 kg
- Diet
- Plant-eaterplant material
- Walked
- On 2 legs
- When
- Late Cretaceous69 to 66 million years ago
- Fossils found in
- Canada, USA
- Named by
- Brown and Schlaikjer (1943)
- Family tree
- Dinosauria › Ornithischia › Neornithischia › Cerapoda › Marginocephalia › Pachycephalosauria › Pachycephalosauridae
Pachycephalosaurs. Two-legged plant-eaters with thick, domed skulls. See all 8
Lived at the same time
- Alamosaurus · same country
- Dryptosaurus · same country
- Edmontosaurus · same country
- Ornithomimus · same country
- Thescelosaurus · same country
- Torosaurus · same country
- Ankylosaurus · same country
- Arrhinoceratops · same country
Other pachycephalosaurs
- Stygimoloch Late Cretaceous
- Dracorex Late Cretaceous
- Homalocephale Late Cretaceous
- Tylocephale Late Cretaceous
- Stegoceras Late Cretaceous
- Prenocephale Late Cretaceous
- Goyocephale Late Cretaceous
Source: Pachycephalosaurus in the Natural History Museum Dino Directory, read 12 November 2026. Sizes are the museum's estimates for a typical adult. "Lived at the same time" lists dinosaurs whose dates overlap, which does not always mean they met.