Encyclopaedia Brittanica describes the Stegosaurus as a quadrupedal dinosaur with a long, spiked tail, a small skull and a series of large, triangular plates covering its arched back. Stegosaurus grew as long as 30 feet.
The plates of the Stegosaurus served as radiators. As each plate contained a supply of blood vessels and alternated position as opposed to forming two rows, the plates were capable of releasing excess body heat or functioning as solar panels in colder environments. The bony, spiked projections at the end of the tail were likely used for defense, but it is possible they were ornamental, according to Encyclopaedia Brittanica.