A Docile Vegetarian

This striking dinosaur is one of the most widely studied in the history of paleontology. The first fossils were discovered by Othniel C. Marsh in 1877 in the American West, during the “Bone Wars.” This quadruped herbivore could measure up to 29.5 feet (9 m) long and weigh up to 2.2 tons (2 metric tons). Because of its small head, it has been used since the 19th century as a symbol of stupidity. It was later shown that most dinosaurs had small brains and that Stegosaurus's brain was larger than average.

Stegosaurus
was an ornithischian dinosaur that belonged to the family Stegosauridae. Its distinctive features included wide plates on its back and four spines, up to 24 inches (60 cm) long, on its tail. The function of these features is still under debate, but it is believed that they served mainly for self-defense. Stegosaurus was an easy victim for the great predators of its time, such as Allosaurus, but it is also believed that it may have been hunted by packs of small predators, such as Ornitholestes. It is doubtful that Stegosaurus could raise itself up on its hind legs, so it probably fed mostly on low bushes.

Head
Its lightweight head had
small teeth that were of
little use for chewing, so it
swallowed plants whole.

Legs
Its front legs were
half as long as its
hind legs. Each
foot had five wide,
short toes.

Tail
Stegosaurus's only
real defense was likely
the four spines on its
tail, which it swung
back and forth.

PLATES
These triangular bony structures were not very solid, but they had a complex network of veins.The plates were likely use to regulate the animal's body temperature or even for courtship.

STEGOSAURUS
Stegosaurus armatus
Size 29.5 feet (9 m)
Diet Herbivorous
Habitat Subtropical Forests
Epoch Late Jurassic
Range North America

WHERE IT LIVED
The first fossils were found in Colorado. Other specimens have since been found in India, western Europe, southern Africa, and China.