This pachycephalosaurus, or boneheaded dinosaur, lived during the Late Cretaceous Period, about 75 million years ago.
The boneheads get their name from the thick skulls they had. It is believed that these skulls might have been used in bunting competitions with rival Homalocephales, or to ram predators or other threats.
Homalocephale was discovered in Mongolia and named in 1974 by Teresa Maryanska and Halszka Osmolska.
The tail of this smaller dinosaur was very stiff, and appears to have been supported by bony rods.
Homalocephale's head, which was much flatter than other members of the bonehead family, was adorned with a number of bumps or studs that probably served to decorate its head and attract mates.