Ceratosaurus means 'horned lizard'. The dinosaur was given this name because it had a row of sharp horns on its head and a row of small, bony pieces of armour running along its back. It is not known what this body armour was for, but it could have been for protection from attack by other Ceratosaurus or larger theropods such as Allosaurus and Torvosaurus.

Scientists have estimated that Ceratosaurus was about six to seven metres long. It seems to have been quite a rare animal - remains of it are much rarer than those of the Allosaurus that lived alongside it.

Ceratosaurus was one of the biggest hunters in the Jurassic Period. Its prey probably included plant-eating dinosaurs, but some scientists have suggested that it may have fed upon aquatic animals such as fish, turtles and crocodiles.

Ceratosaurus is remarkable for the very long, slender teeth in its upper jaw. These teeth could be over nine centimetres long, nearly as long as the lower jaw was deep, so they would almost stick out beyond it when the mouth was closed. Nobody really knows why the teeth were so long, but they may have helped it inflict deep, slashing wounds in prey.