The Schleich® DINOSAURS pachycephalosaur is the largest ornithischian ever discovered to date. It was 4 to 5 meters long, weighed 450 kg and moved on two legs. He was living in North America at the end of the Cretaceous Period. His very rounded skull was 20 to 25 cm thick. Scientists speculate that his skull was used to hit rivals or impress them. The name of pachycephalosaur