Meet the Ankylosaurus – The Dinosaur with a Club Tail

© Warpaint/

Written by Drew Wood

Updated: May 11, 2023

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Over the long history of our planet, there have been millions of species of extinct animals. Most haven’t even been discovered yet. The more paleontologists discover, the stranger the picture of the prehistoric world becomes! One of the more unusual, but less talked-about, species is ankylosaurus. This guy looked a bit like an armadillo on steroids, with a giant club on the end of its tail and armored bumps plating its back. What’s the deal with this warrior of a dinosaur? Let’s find out.

Ankylosaurus in Forest

The ankylosaurus was about the same size as a modern battle tank.

©Daniel Eskridge/

The World of the Ankylosaurus

This beast lived approximately 68 million years ago (the final stage of the Late Cretaceous Period). Paleontologists have discovered fossils all over North America from the middle of the United States in Wyoming to Western Canada in Alberta and Saskatchewan. During this time, these parts of North America would have been rainy forests, plains, and grasslands. Ankylosaurus would have shared this environment with other dinosaurs such as triceratops and edmontosaurus. The dinosaurs during this time were among some of the last living species which ended up going extinct when an asteroid hit Earth and made it uninhabitable for them.

Edmontosaurus 3D

The edmontosaurus was one of the dinosaur species that lived at the same time as the ankylosaurus.


Description of the Ankylosaurus

Boasting a body 20-26 feet long, the ankylosaurus actually was the length of the hull of an M1 Abrams tank (minus the gun). But that 55-ton tank would easily win a shoving match with the “lightweight” five to eight tons ankylosaurus. This guy carried its broad body low to the ground on stout legs. The front legs seem especially capable of absorbing a lot of force, which might mean that it used them for digging. The back of its skull had a set of horns pointing backward, and another set under those pointing back and down.

Despite the battle-ready armor covering its body, the ankylosaurus was not used to fighting for its food. It was a herbivore with a diet similar to that of an elephant: leaves, fruits, ferns, branches, and shrubs. Researchers think it would have eaten about 130 pounds of vegetation a day, which is about the same as a large elephant.

The reason behind its armored body becomes clear when you look at the rest of the ankylosaur’s body and compare it with its predators. It was a short, chunky dinosaur that was mostly slow-moving and poorly equipped to outrun fearsome predators like the fearsome tyrannosaurus rex. If you spent most of your day on the ground with much bigger and quicker carnivores who would love to have a bite of you, you’d probably want some extra chonk and scales on you, too!

3D rendering of a T-rex in a forest of palm-like trees

T-rex was the apex predator in North America during the Late Cretaceous Period.


How Did the Ankylosaurus Use Its Tail?

The club at the end of an ankylosaurus’ tail is best explained as a mass of skin, scales, and bone, called an osteoderm, making a dense and tough ball the size of a badger (24” x 20” x 7”). Scientists have come up with many theories for what this was used for. Some say it was used as a defense mechanism against predators in the fashion of a wrecking ball. If so, it was certainly powerful enough to break the bones of its enemies.

Others favor the theory of disguise – maybe the dinosaur used it to trick predators into thinking the ball was its head! Still others think it was used in fights with its own species. In many species, males battle fiercely for mates, sometimes even to the death. So maybe we need to think of ankylosauruses as being like medieval knights doing battle in the area for the paw of a “lovely” lady.

Where Can You See This Dinosaur Today?

Would you like to get up close and personal with the actual remains of a real ankylosaurus? Check out the specimens at these museums:

American Museum of Natural History, New York City

Canadian Museum of Nature, Ottawa, Canada

Smithsonian Museum of Natural History, Washington D.C.

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About the Author

Drew Wood is a writer at A-Z Animals focusing on mammals, geography, and world cultures. Drew has worked in research and writing for over 20 years and holds a Masters in Foreign Affairs (1992) and a Doctorate in Religion (2009). A resident of Nebraska, Drew enjoys Brazilian jiu-jitsu, movies, and being an emotional support human to four dogs.

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