Dinosaur Facts: Pachycephalosaurus

Setting it different from other dinosaurs, the Pachycephalosaurus had a distinct characteristic , a domed head that consisted of a very thick skull that housed a tiny brain and large eyes. In this article, you will learn more about what the Pachycephalosaurus ate, how they traveled, and where the bulk of their fossils have been found.

Body Features

The rounded skull of the Pachycephalosaurus measured up to 10 inches thick that was surrounded by bony knobs that made this feature look even more imposing. The bumps were found along the snout and along the rear of the skull. The typical Pachycephalosaurus grew to 15 feet long and may have weighed about 950 pounds. It is believed that the dinosaur possessed a decent sense of smell.

The dinosaur had short forelimbs and a stiff tail that possessed a unique mesh of tendons that were interwoven in its rear portion. They had long, powerful hind legs that ended with clawed feet displaying three toes. Their hands were clawed with five fingers.


The Pachycephalosaurus was a herding creature that lived in small groups , choosing coastal and upland regions as their home. When the dinosaur met up with a predator, running was most likely their first line of self-defense. However, some researchers believe that their large dome came in handy and was used to ram rivals during mating rituals or fighting to gain dominance over another Pachycephalosaurus. However, skulls that have been analyzed do not show any proof of healed scars. Unpon further exploration, the thick skull wasn’t as solid as first expected, but instead, fragile when placed under extreme pressure. Using their skull to ram objects would have most likely killed the creature rather than serve as a form of protection.


The Pachycephalosaurus lived during the late Cretaceous period, which dates back about 76 to 65 million years ago , toward the end of the Mesozoic (dubbed the Age of Reptiles). It lived during the same time as the mighty T,Rex. As an herbivore, the Pachycephalosaurus ate soft plants, fruit and seeds , using sharp, small teeth.

It is believed that the Pachycephalosaurs evolved from the Hypsilophodon, which was a small, nimble, bipedal herbivore.

The Pachycephalosaurus was a two-legged dinosaur that wasn’t known for its speed. It is believed that when it did walk or run, it most likely held its back level to the ground. When looking for plant lying low on the ground, the dinosaur probably went on all fours to retrieve its food.

Pachycephalosaurus Fossils

Williams Winkley first discovered Pachycephalosaurus fossils in 1938 on a family ranch located outside of Ekalaka, Montana. However, it wasn’t given a name until 1943 when Barnum Brown and Erich M. Schlaikjer gave the species an identity. Finding complete fossils of a Pachycephalosaurus is rare, but many thick skull fragments have been discovered. The fossils have turned up in Alberta, Canada, the western United States, the Isle of Wight, Mongolia and Madagascar.