One spike 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. Although it looked fierce, Stegosaurus ate mainly low-growing ferns and other plants. It lived in herds that grazed together.
Although S. armatus was the first Stegosaurus species to be found, S. stenops, found by Othniel Charles Marsh, is the more familiar species.
Name: Stegosaurus, meaning ‘roof lizard’
Size: 7.5-9m 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
As well as the plates that Stegosaurus has along its back, it also has two pairs of spikes on the end of its tail to use as weapons. Recent studies show that these spikes stick out sideways. A mass of little bony ossicles protect the throat. The brain is the smallest, when compared with the bulk of the animal, for any dinosaur.
This dinosaur’s tail was long and used for balance, having very short front legs and much shorter back ones to support the weight of its body. It moved on all four legs, stumping heavily along. It could not walk or run very fast and was preyed on by fast-running, carnivorous dinosaurs, such as Allosaurus.
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.
Stegosaurus‘ spiky tail that was very thick and powerful, with bony plates all the way down. Stegosaurus may have used its tail to defend itself, and its young, against any carnivorous dinosaur which came within range.
The back plates were once thought to have been paired, but are now believed to have been in an alternating double row, with the largest plates at the hips, tapering in size towards the head. They may have been covered in horn and used for defence, or covered in skin and used as heat radiators.
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.