Stegosaurus Facts
- Name: Stegosaurus (steg-oh-saw-rus) means ‘roofed lizard’
- Size: up to 7.5m long and 4m high
- Food: low-growing ferns and other plants
- Lived: about 140 million years ago in the Late Jurassic Period in North America
One swipe of its spiked tail and Stegosaurus could cripple any predator that threatened it.
Stegosaurus had a small head, a thick, clumsy body and a spiky tail. Along its back were two rows of bony, diamond-shaped plates. They could grow up to 60–90 cm (2–3 feet) tall and around 60 cm (2 feet) wide. Although it looked fierce, Stegosaurus ate mainly low-growing ferns and other plants. It lived in herds that grazed together.
Big Bodies
This dinosaur was about as long as two cars and weighed about the same. Its tail was long that it used for balance. Stegosaurus had very short front legs and much longer back ones to support the weight of its body.
Stumping Along
It moved on all four legs, stumping heavily along. It could not walk or run very fast and was preyed on by fast running, meat-eating, dinosaurs such as Allosaurus.
Tiny Head
Its small head, which was about the size of a large dog’s, was close to the ground so Stegosaurus grazed mainly on low-growing plants. It had a weak jaw, and could chew only soft, leafy food. Its brain was tiny, about the size of a walnut. This means it had the smallest brain of any animal, compared to its size, that ever lived.
- Stegosaurus had a very small skull and its jaws were weak.
- Case surrounding a rain about the size of a walnut.
- Serrated teeth for cutting plants.
- Horny beak for slicing plants
Spiky Tail
Stegosaurus also had a tail that was very thick and powerful, with bony plates all the way down. At the tip of the tail were four spikes, each one up to 1m long. Stegosaurus may have used its tail to defend itself, and its young, against any meat-eating dinosaur which came within range.
Armour Plating
The plates on Stegosaurus’ back may have been a prehistoric version of solar heating panels, like those in the photograph. These panels work by soaking up the sun’s rays and provide heat for homes, offices and factories today.
On its back, Stegosaurus had a row of bony plates. These grew out of the dinosaur’s skin, and could easily be torn off by a large predator. Some experts think that the plates were a special sort of solar-heating and air-conditioning system which Stegosaurus used to warm or cool its body.
Stegosaurus turned its body so that its plates faced the sun, collecting as much heat as possible in the cool early mornings. Once it was warm enough, it could start moving about and feeding.
Colourful Creatures
Scientists have also suggested that the plates on Stegosaurus’ back may have been very brightly coloured. So the males probably used the plates to warn off other males in the herd and to attract the females at the start of the mating season.