Classification: Reptilia, Ornitischia
Body length: 9 m
Body weight: 3 t
Period: Late Jurassic
Location: North America
Stegosaurus had 17 bony plates that were embedded in its back. The function of these plates is uncertain. Stegosaurus also had spikes at the end of its flexible tail. These spikes were up to four feet long and were used for protection from predators; they pointed to the sides of the tail. 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.Its small brain was only the size of a walnut.