Stegosaurus Fact Sheet

Common Name:

Stegosaurus stenops

Scientific Name:

Narrow-faced roof lizard

Wild Status:

Jurassic Period, 155-150 MYA


North America, Portugal


Portugal, Countries in North America



Life Span:



23 feet long, 7 feet tall at the hips (10 at the top fo the plates), 5 tons

Cool Facts:

  • Rather than relying on armor to defend itself, Stegosaurus evolved one of the most savage defensive weapons in the animal kingdom. Known as a thagomizer, the animal’s tail was studded with four enormous spikes that could measure up to 3 feet long.
  • Instead of the rigid, counterbalancing tail of most dinosaurs, Stegosaurus tails were highly flexible and could even be curled around the animal’s flanks to provide protection from all angles. This maneuverability allowed Stegosaurus to wield its tail almost like a sword to deliver devastating puncture wounds to potential enemies. One Allosaurus specimen was even found with a deep gouge on its pubic bone, indicating that it had been stabbed by a stegosaur though the crotch!
  • Up until recently, Stegosaurus was believed to have a secondary brain in its hips due to the presence of large cavity over the hips near the spinal cord many times larger than its actual brain. This second brain was believed to help control the animal’s rear end. However, current research suggests that this cavity is in actuality a location for a glycogen body or similar structure.


When Stegosaurus was first discovered, it was thought the plates lied flat along the animal’s back in an interlocking pattern like a turtle shell. There has been considerable debate over the years as to the exact arrangement of the plates. Some scientists have postulated they form a single row along the spine, while others theorized they were set up in two paired rows. The most current research suggests that while they were indeed in two rows, these were alternating rather than paired. Contrary to popular belief, the dorsal plates of Stegosaurus made for poor protection. They were surprisingly thin and heavily vascularized, and several specimens have been found sporting allosaur bite marks. More likely they were used for display and/or species recognition, or possibly to help the animal regulate its temperature. Some scientists even speculate the plates could have been able to change color.

Taxonomic Breakdown:

Kingdom - Animalia Phylum - Chordata Class - Reptilia Order - Ornithischia Family - Stegosauridae Genus - Stegosaurus Species - S. stenops

Conservation & Helping:

The Stegosaurus is currently extinct, and was believed to exist 155 - 150 Million Years Ago

For Teachers and Educators


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