PACHYCEPHALOSAURUS

Thick-headed lizard/reptile

Pachycephalosaurus, genus of large and unusual dinosaurs found as fossils in deposits of North America dating to the Late Cretaceous Epoch (about 100 million to 65.5 million years ago).

Pachycelphalosaurus’s skull was about 20 times thicker than most other dinosaur noggins, so its name makes sense—it means “thick-headed lizard.” This nine-foot-long dino also had short, spiky horns surrounding the dome and extending down to its nose. But that might not how this dinosaur always looked. According to recent research, youngsters might’ve had had spikier skulls and no dome at all.

It also had other teeth in its cheeks. That might have helped it grind up things like nuts and fruits.

Length : 5 meters (16 ft) | Height : 2 meters (6 ft)