Stegosaurus, the "Roofed Lizard," is the most famous member of the Stegosauridae family, which is known for its unique body armor consisting of plates and spines. Stegosaurus is also the largest in its family at almost nine meters long and four meters tall. Originally depicted with its plates laying flat on its back like roof tiles, the famous plates of the Stegosaurus stood up on its back in two offset rows. The purpose of these plates is still debated, but they were likely for sexual display, thermoregulation, or intimidation. The spikes on its tail are known as "thagomizers," a name popularized by Gary Larson's Far Side comic. As its main source of defense, the tail could be swung with great force at foes, goring them with the sharp spikes. Living alongside Allosaurus in Late Jurassic United States and Portugal, Stegosaurus had good reason to have such a strong defensive system. It was one of Allosaurus's many food sources, so fighting back against the mighty predator was a necessity. It was successful, too; one Allosaurus fossil contains a puncture would that almost certainly came from a thagomizer. When it wasn't protecting itself, Stegosaurus travelled in herds eating low-level plants like mosses or fruit. Rearing on its hind legs would let it reach heights of up to six meters.