BBC Earth


'Roof lizard'


Stegosaurus walked on four rather stumpy legs. It had a double line of leaf-shaped plates running down its back. Stegosaurus was the largest of the stegosaurs.

They call it home

The Morrison Formation is a long stretch of ancient rock running from Montana, all the way to New Mexico. Amazingly, it had been preserved for the last 150 million years, just waiting for a palaeontologist to uncover its ancient wonders. For palaeontologists, it is a Jurassic playground – its treasures include fossils of Allosaurus, Diplodocus, Brachiosaurus and Apatosaurus.

What big teeth you have

What big teeth you have

Stegosaurus' teeth were small, triangular and flat.

Nose knowledge

Nose knowledge

Stegosaurus may have had an excellent sense of smell for smelling out its fragrant food choices.

The most fantastic find

The most fantastic find In 2007, Fernando Escaso, from Madrid University, led a team of Spanish and Portuguese scientists, to the dinosaur-rich Casal Novo in Portugal. The team struck lucky unearthing the very first Stegosaurus fossil to be found outside of North America. This led scientists to believe that there may have been a walkway between the two continents during the Jurassic. A Stegosaurus could have literally been able to go from America to Europe in one small step.

Stegosaurus features

Stegosaurus features Height: 3.7m (12.14ft)
Length: 9m (29.52ft)
Weight: 3 tonnes (3.36 short tons)
Top speed: 6kph (3.73mph)
Vision: Stegosaurus not only had a small brain but also had poor eyesight. They were not very clever animals.
Skin: Stegosaurus probably had tough, scaly skin – prehistoric armour in a Jurassic battleground. Stegosaurus had dermal plates rising from its skin like sails – the largest plates were a massive 60cm (23.6in) wide and 60cm (23.6in) tall.
Brain: Stegosaurus had a brain the size of a kitten (even though its body weighed as much as 2,756 kittens).
Prey: Stegosaurus was first thought to have been bipedal because of its extremely short forelimbs, but they would have actually allowed it to graze low to the ground. Stegosaurus was a dedicated plant eater and would have spent most of its time eating mosses, ferns, horsetails, cycads and conifers.
Bite: Stegosaurus had a bite force of 140.1 newtons, which is less than half the bite force of a labrador. It didn't need a big bite for its vegetarian lunch.

Stegosaurus facts and theories

Stegosaurus facts and theories

  1. Stegosaurus was a dedicated plant eater and would have spent most of its time eating mosses, ferns, horsetails, cycads, conifers or fruits.
  2. Stegosaurus was a member of the subgroup of dinosaurs called Ornithischia: the bird-hipped dinosaurs.
  3. We do know that Stegosaurus' plates could have been used for threat or courtship displays and would have had the ability to blush red when flushed with blood.
  4. In addition to the flat plates along its back, Stegosaurus also boasted a double set of fierce spikes on its tail. A recent study using advanced computer modelling shows that the tail of stegosaurs was flexible enough for the spikes to be swung at fast speeds, like a medieval mace. This would have been a useful weapon against predators.
  5. Stegosaurus had an extremely slow maximum speed, only slightly faster than a human walking. A stegosaur had no chance of outrunning Allosaurus.
  6. The dinosaur's digestive system was not powerful enough to process such tough Jurassic vegetation. A number of herbivorous dinosaurs would swallow stones to mash up vegetation in their stomachs as a kind of prehistoric liquidiser.