Pachyrhinosaurus
- Pronunciation: PAK-ee-rye-no-SAWR-us
- Translation: Thick-nosed Lizard
- Order: Ornithischia
- Suborder: Marginocephalia
- Infraorder: Ceratopsia
- Family: Ceratopsidae
- Height: 11 feet (3.5 meters)
- Weight: 8,000 pounds (3,630 kg)
- Length: 23 feet (7 meters)
- Period: Late Cretaceous
- Description: Herbivore, Quadrupedal
- Notes: Found in Alaska and Alberta, Canada, Pachyrhinosaurushad a large oval plate of bone on its nose instead of a horn. Rival males may have used their horns in butting combat to establish dominance within the herd. The horns may also have been usedfor defense against the carnosaurs that stalked them.