Profile view of Stegosaurus stenops
Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Superorder Dinosauria
Order Ornithischia
Suborder Stegosauria
Family Stegosauridae
Subfamily Stegosaurinae
Genus Stegosaurus
1st Species Stegosaurus stenops
Other attributes
Time Range 155-150 mya
Location United States of America, Portugal
Name Meaning Roofed reptile
Physical Dimensions 9.3 meters long for S.stenops
Weight 6 tonnes for S.stenops
Dietary Classification Herbivore

Stegosaurus is a stegosaurid stegosaurian thyreophoran dinosaur from the Late Jurassic of the United States of America and Portugal. It was named in 1887 by Othniel Charles Marsh. It is one of the most famous dinosaurs to exist (only being slightly overshadowed by Triceratops, Brontosaurus, and Tyrannosaurus), noted for its back plates and spiked tail.


Stegosaurus was a quadrupedal dinosaur with a bulky body, 4 erect legs, a long tail, a moderately long neck, and a small head with a large beak. Perhaps the most defining traits of Stegosaurus were the row of large, diamond-shaped, keratinous plates running down its back, as well as the 2 pairs of spikes on the tip of its tail; this spiked tail is popularly known as a thagomizer. Its body was covered in scaly skin, with a large clump of osteoderms covering its throat, and a few crocodile-like scutes running down its hips.


Stegosaurus was an herbivore, feeding on mosses, ferns, horsetails, cycads, and conifers. Its beak was used to strip branches of their leaves, while the many small, flat teeth in the back of its mouth were used to grind up vegetation.


The use of the plates running down Stegosaurus' back is yet unknown; some people have said that they were used for regulating body temperature, while others have said they could be pumped full of blood in order to flush bright red and intimidate foes. As well as this, the large thagomizer on its tail was thought to have been used as a weapon against predators like Allosaurus and Torvosaurus; this has been confirmed, as an Allosaurus skeleton was found with a thagomizer puncture hole in its pubic bone. Earlier, Stegosaurus was thought to have had a weak bite, and could only feed on soft vegetation; however, recent studies have shown that it had a bite force comparable to that of modern herbivorous mammals, and so, it was able to process tough plants such as cycads. An interesting thing to note is that due to Stegosaurus' small head and braincase, people thought it would have needed a second brain in its abdomen in order to function properly; this theory has now been discredited, and the extra abdominal orifice thought to have housed that second brain is now hypothesized to be a source of glycogen for the animal's body.

In popular cultureEdit

Stegosaurus was first introduced to the public in the 1912 novel, The Lost World, where it is one of the many herbivorous dinosaurs encountered by the exploration crew. Since then, it has managed to become extremely popular, appearing in major pieces of media like King Kong, Fantasia, The Land Before Time, and Jurassic Park; in those pieces of media, it is often shown as either trying to bludgeon humans with its thagomizer or fighting against a Tyrannosaurus (commonly depicted a ruthless carnivore ready to take a bite out of anything it sees). In its earlier pop culture appearances, Stegosaurus was commonly depicted as a slow, tail-dragging behemoth more unintelligent than the dumbest birds (other large dinosaurs, such as Tyrannosaurus, Brontosaurus, and Triceratops weren't treated any nicer than it was); however, in its more recent pop culture appearances, it has become more vigorous and graceful.

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