Stegosaurus

The Stegosaurus is easily recognized all over the world over, as one of the best known of all the dinosaurs ever. It roamed the open plains of the Late Jurassic Period in what is now North America. The unique plates along its back, its small head and spiked tail make it a peculiar and unique dinosaur. This plant-eater evolved to find its food in the low-growing plants of the late Jurassic. The long fearsome spikes on its tail would have made a powerful weapon against any hungry predators.

Stegosaurus is often called the dumbest dinosaur because of its incredibly small brain. In fact, most scientists believe that its brain was too small to control such a large creature and that it used an auxiliary "brain" located above its rear legs to help control its movements. This was not actually a brain, but a bundle of nerves that helped relay information from its real brain. Its brain was once thought to have been the size of a walnut, but CAT-scans proved that it was actually the size of 5 walnuts.

Most fascinating to people are the plates along its back. There has been a great deal of debate about their use and arrangement. The plates were up to 2-feet tall and 2-feet wide (.6 m). The most prevalent theory is that they were used for cooling or heating the animal. A more recent theory, however, suggests that they could have been used as a display during courtship and that they may have been brightly colored. It is also possible that they could move up and down, perhaps to intimidate predators.

The spikes on its tail are also the subjects of some controversy. For years every model of Stegosaurus showed it with the spikes sticking up into the air. It is only since the 1990s that it has become accepted that these spikes stuck out horizontal to the ground, which would have been a potent defensive weapon when swung at a hunter.

Stegosaurus would have lived in family groups and herds, moving slowly through forests while eating the low-growing plants. Its front legs were considerably shorter than its hind legs, making it adapted to nibbling the plants closest to the ground. Stegosaurus is the namesake for a large family of dinosaurs whose members were found all over the world. The Stegosaurus (its code name "Stego") was a peaceful herbivore, and probably roamed the prehistoric highlands in herds that size from small to large numbers, grazing on low ground plants. An average Stegosaurus was about the size of an elephant, standing about 11 feet tall. It had a very low intelligence (its brain was the size of a walnut). The bony plates on its back may have served a dual purpose of a body temperature regulation, and protection from large flesh-eating predators. Different species had different numbers of tail spikes. For example, Stegosaurus stenops had 4 spikes, Stegosaurus ungulatis had 8 spikes.