Stegosaurus means “roofed lizard“, because when the fossils were first discovered, scientists thought the 17 plates were arranged horizontally like roof tiles. It turns out that these plates were arranged vertically. The blood supply suggests they played a role in thermoregulation and could quickly turn red. Other hypotheses suggest they could have been used for mating displays or defense. In fact, in some species today, appendages that can turn red are used to attract a mate and/or scare away predators.
The 4 bony spikes from 0.6 to 1 meter long at the end of its tail served as defensive weapons.
A second brain?
During the first fossil observations, a cavity in the pelvis area suggested it had a second brain. In reality, this cavity housed a nerve center to coordinate the back of the body. Another hypothesis suggests this cavity was a carbohydrate reserve for the body.