The stegosaurus (roof lizard) is the most familiar Dinosaur for its distinctive physical feature. They were the animals that existed during the late Jurassic period about 146-150 million years ago. The Fossils have been found in Colorado, Utah, and Wyoming have established the fact that Stegosaurus was around 26-30 feet long and about 9 feet tall. The weight was approximately 6,800 pounds. As compared to the large body the brain was very small of the size of the walnut. Its weight was about 2.5 to 2.9 ounces. The skull was pointed, narrow and long. The animal had small cheek teeth and toothless beak.

The 17 bony plates rooted on the back of the stegosaurus. These bony plates were in two rows and were placed alternately to each other. The plates were made of hollow bones filled with tube-like tunnels but their functions are still unknown. The plates were possibly well nourished by blood vessels and may be either used for protection or to regulate the body temperature.

Stegosaurus protected themselves from the predators with the help of spike they had at the end of their flexible tails called Thagomizer. The armor- like scutes on the skin of the neck and on the pelvic area was also helpful for protection.

It had long and straight rear legs, which spread out to the sides. The rear foot possessed three short, wide toes with hooves whereas the forefeet had five short wide toes with short, hoof like tips. They were one of the last of Stegosaurids.