Say it: STEG-oh-SORE-us · Name means: “Roof lizard”
Key facts about Stegosaurus
⏳ Lived
155–145 million years ago Late Jurassic
🌿 Diet
Herbivore (plant-eater)
📏 Length
7–9 m (23–30 ft)
↕️ Height
2.8–4 m (9–13 ft)
⚖️ Weight
3,500–7,000 kg (7,720–15,430 lb)
📍 Found in
North America, Europe
🔎 Discovered
1877 by Othniel Charles Marsh (fossil found by Arthur Lakes)
About Stegosaurus
Stegosaurus had two rows of big bony plates along its back and four sharp spikes on its tail. It was a bus-length plant-eater with a surprisingly small head.
Stegosaurus was a large thyreophoran from the Late Jurassic Morrison Formation of North America, with possible remains in Portugal. Its alternating back plates were probably for display, while its tail spikes were real weapons, as shown by a wounded Allosaurus bone.
Drawn to scale next to a 1.7 m adult and a 12 m school bus.
Did you know?
Stegosaurus had a head about the size of a horse's head on a body as long as a bus!
The biggest plates on its back were taller than a kitchen chair.
Its tail spikes are nicknamed the 'thagomizer', after a funny cartoon.
Scientists found an Allosaurus bone with a hole poked in it by a Stegosaurus tail spike!
An Allosaurus tail vertebra from the Morrison Formation has a healed puncture that matches the shape and size of a Stegosaurus tail spike, showing the 'thagomizer' was used in defence.
The plates were covered in keratin and riddled with blood vessels; ideas for their use include display, species recognition and temperature control, with display currently the favoured explanation.
'Sophie', at the Natural History Museum in London, is the most complete Stegosaurus skeleton known, and has helped scientists study how it moved and fed.
Bite-force studies suggest Stegosaurus had a weak bite, so it probably ate soft, low plants rather than tough branches.
Scientists debate how many Stegosaurus species are valid, and whether the name for the main species should be S. stenops or S. ungulatus.
DinoVerse · Dinosaur fact sheet
