STEGOSAURUS (STEG-o-sawr-us) "Plated Lizard" (Greek stego- = roofed or plated + sauros = lizard, referring to the plates on its back)
The only plated dinosaur ever found in North America. It has also been found in Europe. This four-legged plant eater was 11 feet (3.4 m) tall at the hips and 25 feet (7.5 m) long. Its body was about the SIZE of an Asian Elephant. Stegosaurus had a ridiculously small head and a golf-ball-sized BRAIN. Some people think that an enlargement of the spinal cord above the hips was a second brain, but it was not. All four-legged animals have this.

Stegosaurus was high at the hips and low at the shoulders, causing it to cary its head low. It probably ate low ground plants. Its long, heavy TAIL was armed with four spikes, each about 1 foot (30 cm) long. Two rows of large, thin, leavlike, bony plates arranged alternately (rather than in pairs) ran down its neck and back and partway down its tail. The largest plates were 2 feet (60 cm) wide and 2 feet (60 cm) talkl. these were situated over the hips. No one knows the purpose of these plates. They might have been used to attract a mate, or as a DEFENCE mechanism - perhaps they made the animal look larger. The most recent theory is that they helped control the body temperature. (Wind flowing around the plates would have cooled the blood flowing through them.)

Stegosaurus lived during the LATE JURASSIC PERIOD. Many skeletons of this dinosaur have been found in Colorado, Utah, and Wyoming. One skeleton was a baby about the size of a German shepherd dog. Another was found with its plates in position.

Classification: Stegosauridae, Stegosauria, Ornithischia