Sphaerotholus is a group of Pachycephalosaurian dinosaurs that used to live in the western United States and Canada during the Late Cretaceous period.  

Key Facts

Sphaerotholus pronunciationSphe-ro-tho-las
What does Sphaerotholus mean?The name Sphaerotholus came from two combined Greek words; sphaira, meaning ‘ball’ and tholos which means ‘domes’.
Dinosaur typePachycephalosauria
On the menuHerbivore
Length2 meters (6 ft)
HeightSince the fossils recovered are only skulls, it’s a bit hard for the researchers to measure their exact height.
Weight100 lbs
Life expectancyThe information about its average lifespan is still unknown though researchers believe that it existed around 70 million to 65 million years ago.
Legs used to get aroundBipedal
Estimated top speedTheir estimated top speed is not known, but it’s assumed that with their small size, they could be fast-moving dinosaurs.
When they livedThough researchers are quite unsure of the exact numbers, most of them assume that Sphaerotholus used to roam the Earth about 70 million to 65 million years ago during the Upper Cretaceous period.
Where they have been found?Sphaerotholus existed in the western part of the United States and Canada. They are known to be terrestrial and live in desert environments.

When & Where

Due to the lack of data in resources, there was no specific year and location where the fossils of the Sphaerotholus have been recovered. However, it is said to be one of the first Pachycephalosaurian dinosaurs to be discovered in North America. It was first described by Williamson and Carr in 2002.

Size & Weight

Sphaerotholus are known to be small herbivorous dinosaurs. Though their height is still unknown, they measure about 2 meters (6 ft) in length and weigh around 100 lbs. 

Mobility & Diet

Sphaerotholus were plant-eaters, which means that their diet was mainly plant materials. However, some scientists still suggest that they might also have been an omnivore. 

Interesting Points

  • Since there are only a few details about this dinosaur, it is said that we can compare them well with the Stegoceras and Prenocephale dinosaurs since they are known to have the same size and physical traits as Sphaerotholus. It was even considered by Sullivan as a synonym for Prenocephale.
  • Sphaerotholus reproduce by laying eggs, like most of its kind.
  • Paleontologists were able to recover 11 different specimens of Sphaerotholus.
  • They existed during the Maastrichtian Age.