Pachycephalosaurus

The thick-skulled headbutter of the Cretaceous/Dinosaurs & Extinct Animals

Pachycephalosaurus wyomingensis lived about 70 to 66 million years ago during the Late Cretaceous in North America. Its domed skull was up to 25 cm thick, surrounded by bony knobs and short spikes. Whether it actually used its skull for head-butting combat is debated; some scientists suggest the dome was used for flank-butting or display instead. The animal was about 4.5 meters long and weighed roughly 450 kg. It was one of the last non-avian dinosaurs before the mass extinction.