Ankylosaurus
Ankylosaurus was a walking tank covered in bony plates and armed with a heavy club on its tail. It lived at the very end of the Age of Dinosaurs, about 68 to 66 million years ago, in what is now North America. Despite its scary look, it was a gentle plant-eater that used its tail club to defend itself from big predators like Tyrannosaurus rex.1

When did it live?
How big was it?
Fun facts
Ankylosaurus is one of the largest known ankylosaurids, with an estimated length of up to 8 metres (26 feet).12
Its body was covered in bony plates called osteoderms, and it had a large half-ring of armour across its neck and shoulders.2
The tail club was made of fused bones and could be swung powerfully from side to side to deliver devastating blows to attackers.1
Ankylosaurus had a long, low skull with prominent horns that stuck out sideways or upwards.2
Scientists have never found a complete Ankylosaurus skeleton, so some details about its armour arrangement remain unknown.1
It moved slowly on four legs, but could probably speed up when it needed to escape danger.1
Some scientists think Ankylosaurus might have used its front limbs for digging, perhaps to find roots or other food.1
Myth buster
Myth: Ankylosaurus used its tail club to attack and kill prey.
Truth: Ankylosaurus was a herbivore and only used its tail club for defence against predators, not for hunting.1
For dino experts
- Scientific name
- Ankylosaurus
- Named by
- Brown 19083
- Group
- Armoured dinos
- Family / clade
- Ankylosauridae3
- Classification
- Ornithischia > Ankylosauria > Ankylosauridae > Thyreophora3
- Age of the rocks
- 84 to 66 million years (Campanian to Maastrichtian)3
- Rock formations
- Ferris, Hell Creek, Lance3
- Countries
- USA, Canada3
- Fossil records
- 16 in the Paleobiology Database3
- Discovery
- The first Ankylosaurus bones were found in 1906 in the Hell Creek Formation of Montana, USA, by a team led by Barnum Brown. Brown named the species Ankylosaurus magniventris in 1908.13
- Still debated
- Scientists still debate exactly how the back armour of Ankylosaurus was arranged, because no complete skeleton has been found.1
Where the facts come from
- Ankylosaurus | Natural History Museum (nhm.ac.uk)
- Redescription of Ankylosaurus magniventris Brown 1908 (Ankylosauridae) from the Upper Cretaceous of the Western Interior of North America (cdnsciencepub.com)
- Ankylosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.
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