What it looked like
Its skull was long and narrow; it had a toothless beak and small cheek teeth. Its head was carried close to the ground, probably no more than 1 m high.

Stegosaurus had 17 bony plates that stuck in its back. Since they were not attached to its bones, no one is sure exactly how they were positioned. The plates were made of bone which was not solid, but was filled with tube-like tunnels. They may have also been used for protection or mating display purposes.

Stegosaurus also had tail spikes at the end of its flexible tail. These spikes were up to four feet long and were used for protection from predators.

Stegosaurus' rear legs were longer and straighter than its front legs, which sprawled out to the sides. The feet of the front legs had five short, wide toes with short, hoof-like tips. The rear feet had three short, wide toes with hooves.

What it ate
This plated dinosaur was an herbivore (it ate only plants). It must have eaten a large amount of plant material each day to keep alive. Scientists don't agree whether or not Stegosaurus could stand up on its rear legs to reach for food. If it couldn't rear up, it was limited mostly to plants no taller than about 1 m tall. This would have included ferns, mosses, and other small plants.

How it moved around
Stegosaurus walked slowly on four legs. Its back legs were twice as long as its front legs.

How it probably behaved
Stegosaurus may have been a herding animal, but this is far from certain. It had an extremely tiny brain, so it was not very intelligent at all.