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.
