The Pachycephalosaurus from Schleich DINOSAURS is the largest beaked, herbivorous dinosaur ever discovered. It grew to around 4-5 m in length, 450 kg, moved on two legs and lived in the Late Cretaceous period in North America. Its strong domed skull was 20-25 cm thick. Scientists believe that it used the skull to ram or impress rivals. Pachycephalosaurus means thick-headed lizard.