Stegosaurus was the largest of the Stegosauridae or plated dinosaurs. It was just a little larger than a modern day elephant.
It had a long, narrow, pointed skull and a toothless beak.Stegosaurus had a very small brain, about the size of a walnut. It seems kind of strange that such a big animal would have the brain the size of a squirrel, but it's true. Some people wonder if they had a second brain somewhere that was used just to control its legs and tail. Their rear legs had three short, wide toes with hooves and were longer and straighter than its front legs which had five short, wide toes with short hooves. They had very strong legs and it could stand up on its hind legs to reach for leaves on low branches.
Stegosaurus plates were in two rows and were alternated in alignment. This is how the dinosaur got its name, which means "roofed lizard" or "covered lizard". These plates were covered in thorns and used in defense or they were covered with skin and used to control their body temperature. To keep warm it would direct the plates towards the sun or place them into the wind to cool off. Obviously, Stegosaurus is a cold blooded dinosaur because of this.Stegosaurus may have roamed the land in small herds,as suggested by footprints.
The end of Stegosaurus' tail had four long sharp spikes, that were no doubt used to protect itself against large meat-eaters. This plated dinosaur was an herbivore (it ate only plants). It must have eaten a large amount of low-calorie plant material each day to sustain its bulk, probably using its toothless beak to get food. There is debate on whether or not Stegosaurus could rear up on its rear legs to forage for vegetation. If it couldn't rear up, it was limited mostly to plants no taller than about 3 feet (1 m) tall.
Possible predators of Stegosaurus include all the large meat-eaters from western North America during the Late Jurassic Period, about 156-140 million yeas ago (where and when Stegoaurus lived). Some of these meat-eaters included Allosaurus, Ceratosaurus, Marshosaurus, Torvosaurus, and maybe even packs of smaller meat-eaters like Ornitholestes.