Ankylosaurus facts for kids

Quick facts for kids Ankylosaurus Temporal range: Late Cretaceous, 70–66 million years ago
Cast of Ankylosaurus skull at the Museum of the Rockies
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Order:	†Ornithischia
Family:	†Ankylosauridae
Tribe:	†Ankylosaurini
Genus:	†Ankylosaurus Brown, 1908
Species:	†A. magniventris
Binomial name
†Ankylosaurus magniventris Brown, 1908
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Ankylosaurus was a huge armored dinosaur that lived at the very end of the Late Cretaceous period. This was between 70 and 66 million years ago in western North America. It was one of the last non-bird dinosaurs on Earth before the big Cretaceous–Paleogene extinction event. The famous fossil hunter Barnum Brown named it in 1908. Its name means "fused lizard" because many bones in its skull and body grew tightly together. Its full scientific name, Ankylosaurus magniventris, means "fused lizard with a great belly."

This amazing animal was built like a living tank. It walked on four legs and had wide, thick bones. Scientists believe it grew between 6 and 8 meters long. It could weigh up to 8 metric tons. Its body was covered in hard plates, and it carried a heavy club on the end of its tail.

The Discovery of Ankylosaurus Fossils

Skull of the first specimen and drawing

The first Ankylosaurus fossil was found in 1906 in Montana. It was discovered in the rocky layers of the Hell Creek Formation by a team led by Barnum Brown. This find included parts of a skull, vertebrae, ribs, and over thirty bony armor plates called osteoderms.

Later, in 1910, Brown found another specimen in Alberta, Canada, inside the Scollard Formation. This specimen was very special because it had a complete skull and the very first preserved tail club. More bones and teeth were later uncovered in the Lance Formation in Wyoming and the Frenchman Formation in Canada. Even though it is famous, scientists have only discovered a few partial skeletons so far.

What Did Ankylosaurus Look Like?

Size of Ankylosaurus compared to an adult human

Ankylosaurus was the biggest member of its dinosaur family, called the Ankylosauridae. It had a very wide, low skull that looked triangular from above. Two backward-pointing horns grew from the back of its head. Unlike its close relatives, its nostrils pointed sideways instead of straight forward. It had a tough beak for snipping plants and small, leaf-shaped teeth farther back in its mouth.

Built Like an Armored Tank

How the armor plates may have looked

The most famous feature of Ankylosaurus was its heavy body armor. Bony plates called osteoderms were set directly into its thick skin. These plates covered its back, neck, and sides. Two half-rings of bone shielded the top of its neck.

Small bony buttons filled the spaces between the larger plates so the dinosaur could still bend its body. Unlike some other armored dinosaurs like Edmontonia, it did not have long spikes on its shoulders. Instead, its plates were flatter with gentle ridges across them.

The Dangerous Tail Club

Tail club fossil at the American Museum of Natural History

At the very tip of its tail, Ankylosaurus carried a massive weapon. This tail club was made of large osteoderms fused around the final tail bones. The last few vertebrae in the tail were locked tightly together to form a stiff handle.

Special muscles allowed the dinosaur to swing its tail sideways with incredible power. Scientists think this tail club was used to fight off giant predators like Tyrannosaurus. A single strike had enough force to break the leg bones of an attacker. The dinosaurs may have also used their tail clubs to gently shove rivals of their own species.

How Did Ankylosaurus Live?

Ankylosaurus in its prehistoric home

Ankylosaurus was a plant-eating herbivore. It held its head close to the ground, feeding on low-growing ferns and shrubs. Its broad beak allowed it to take large mouthfuls of greenery at once.

Because its teeth were tiny, it did not chew its food very much. Instead, it probably had a very large belly where plants fermented and broke down slowly over time. Some paleontologists think its strange nostrils and sinuses helped it smell things far away or warmed the air it breathed.

This tough dinosaur shared its coastal forest home with many famous creatures. These neighbors included horned giants like Triceratops, duck-billed dinosaurs like Edmontosaurus, and dome-headed dinosaurs like Pachycephalosaurus. It lived successfully in this prehistoric world until the age of dinosaurs came to an end.

Images for kids

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  Skull cast

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  Digging up bones in 1910

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  Fossil skull AMNH 5214

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  Leaf-shaped tooth

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  Life reconstruction

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  Neck armor pieces

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  Bones identified in 2017

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  Comparison of armored skulls

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  Armor patterns on the skull

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  Neck bone

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  Tail bone

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  Back bone with wide ribs

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  Large skull specimen

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  Air passages inside the snout

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  Shoulder bone

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  Bony armor pieces

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  Comparison of tail clubs

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  Map of fossil discoveries

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  Model shown at the 1964 World's Fair

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  Early drawing from 1908

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  Outdated 1908 drawing