Due to its distinctive tail spikes and back plates, Stegosaurus is one of the most recognizable dinosaurs, along with Tyrannosaurus,
Triceratops, and Apatosaurus. The name Stegosaurus means "roof-lizard", a reference to the armor plates on its back that were originally thought to lay flat on the animal like shingles on a roof.
The spikes were most likely used for defense, while the plates have also been proposed as a
defensive mechanism, as well as having display and thermoregulatory (heat control) functions.
The Stegosaurus lived some 155 to 145 million years ago, in an environment and time dominated by the giant sauropods.