An Ultimate Guide to Ankylosaurus: The Clubbed Tail

Leave a comment / / Updated on: 4th January 2024

Name MeaningFused LizardHeight1.4 to 1.7 meters (4.5 to 5.5 feet)
PronunciationAn-kye-low-sore-usLength6.25 to 10 meters (20.5 to 32.8 feet)
EraLate Cretaceous (Maastrichtian)Weight4.78 to 7.95 metric tons (5.26 to 8.76 short tons)
ClassificationDinosauria,‭ ‬Ornithischia & ThyreophoraLocationNorth America (USA)

Ankylosaurus Pictures

A pair of ankylosauruses graze in a watery lowland
A pair of ankylosauruses graze in a watery lowland | Daniel Eskridge via GettyImages

The Ankylosaurus

Gage Beasley Prehistoric's Ankylosaurus Concept
Gage Beasley Prehistoric’s Ankylosaurus Concept

One of the world’s most famous armored dinosaurs – the renowned Ankylosaurus!

The species name, Ankylosaurus magniventris, translates as “bent/fused lizard” with “great belly,” which says a lot about this creature’s appearance!

Although no complete skeleton has been recovered, scientists have shown tremendous curiosity about the species.

As such, the Ankylosaurus has been well studied, and thanks to dedicated researchers, we can now discuss where it lived, what it looked like, what it ate, and who shared its habitat!

Let’s start our discussion by revealing that the Ankylosaurus is among the world’s latest non-avian dinosaurs, having lived during the Late Cretaceous, around 68-66 million years ago.

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection

Its fossils were found in western North America’s geological formations.

The species is widely known for its lightweight body armor, which is excellent at protecting the robust prehistoric creature!

Another unique characteristic of the Ankylosaurus is the tail club, which was greatly used in intraspecific combat!

Do you want to learn more details? Keep reading, as we’ve got an amazing Ankylosaurus guide!

Physical Characteristics

Ankylosaurus on a dry land
Ankylosaurus on a dry land | ALLVISIONN via GettyImages

The Ankylosaurus is probably the largest dinosaur species in the Ankylosauria suborder.

Its average length was calculated based on skull sizes. As such, scientists estimate that an Ankylosaurus with a skull length of 64.5 centimeters (25.3 inches) and a width of 74.5 centimeters (29.3 inches) measured approximately 6.25 meters (20.5 feet) long!

Even the smallest skulls belonged to dinosaurs, measuring around 5.4 meters (17.7 feet) long!

Further discoveries and comparisons revealed that the Ankylosaurus could’ve measured up to 10 meters (32.8 feet) long.

However, all these numbers are pure estimations. The length of Ankylosaurus is still debatable and will remain so until other information-bearing fossils are discovered.

This is also valid for the height and weight of the species.

Gage Beasley Prehistoric's Ankylosaurus Size Comparison
Gage Beasley Prehistoric’s Ankylosaurus Size Comparison

The height of the same individuals was estimated at around 1.4-1.7 meters (4.5-5.5 feet) tall at the hips.

The weight was estimated at approximately 4.7-7.9 metric tons (5.1-8.7 short tons). However, as mentioned, these numbers are still up for debate.

The recovered skull fossils helped scientists discover more about Ankylosaurus physiology. Here are some things specialists agreed on:

  • The skull was wider than it was long.
  • The dinosaur had a broad beak.
  • The eye sockets were slightly oval.
  • It had four horns.
  • The nostrils faced sideways.
  • The teeth were small, leaf-shaped, and featured smooth sides.
  • The teeth were taller than they were wide.

The skull is probably the most complete part of the Ankylosaurus. The physiology of the rest of the body remains largely unknown. However, scientists were able to outline an estimative appearance.

Presumably, Ankylosaurus was a quadrupedal dinosaur. Its hind limbs were longer than its short limbs.

The massive head was supported by large ligaments, and the dorsal vertebrae were tightly spaced, thus limiting the dinosaur’s movements.

Apart from this, details about the Ankylosaurus’s appearance remain a mystery.

Possible back osteoderm (holotype), in outer and inner view
Possible back osteoderm (holotype), in outer and inner view | Barnum Brown via Wikipedia

Armor fossils were discovered as well. Although several possible armor arrangements were proposed, none are set in stone.

Presumably, the Ankylosaurus was covered in large osteoderms, small interstitial osteoderms, and ossicles.

The large osteoderms were probably arranged in rows across the body, from head to tail. They measured up to 35.5 centimeters (13.9 inches) in length and were smooth, thin-walled, and flat.

The neck of the dinosaur was most likely covered in what scientists call cervical half-rings.

The osteoderms were lightweight but presumably strengthened by collagen fibers.

Moreover, since their roots were in the bone tissue, the osteoderms were very durable, thus providing the Ankylosaurus with excellent defense.

The Ankylosaurus had a tail club as well. In simpler terms, a tail club is a bony mass at the end of the dinosaur’s tail.

It consisted of two large osteoderms, two smaller ones at the tip, and small osteoderms arranged in a row at the midline.

Gage Beasley's Ankylosaurus Dinosaur Soft Stuffed Plush Toy
Gage Beasley’s Ankylosaurus Dinosaur Soft Stuffed Plush Toy

Habitat and Distribution

Ankylosaurus fossils were recovered from Montana, Wyoming in the United States, Alberta and Saskatchewan in Canada.

The type specimen belongs to Montana’s Hall Creek Formation. Other formations hosting fossils belonging to this genus are the following:

  • Lance and Ferris Formations, Wyoming, United States
  • Scollard Formation, Alberta, Canada
  • Frenchman Formation, Saskatchewan

These formations are characterized by a broad coastal plain extending toward the Rocky Mountains.

They likely consisted of mudstone and sandstone, thus indicating floodplain environments.

The climate was subtropical or temperate. Tropical storms and forest fires weren’t uncommon.

However, because few fossils were found, scientists suspect they were probably rare in the abovementioned formations.

Or it might’ve just been a rare visitor to the coastal plain depositional environment, thus limiting fossilization.

Other studies suggest that the Ankylosaurus preferred coastal lowland settings, although this requires further research and confirmation.

Behavior and Diet

A pair of ankylosauruses graze in a watery lowland
A pair of ankylosauruses graze in a watery lowland | Daniel Eskridge via GettyImages

Here are some things researchers mention in their papers regarding Ankylosaurus behavior:

  • Juvenile Ankylosaurus specimens are thought to have lived in small congregations. Adults, however, likely lived alone.
  • Fossil discoveries show it was a slow-moving animal, although it could make quick movements if required.
  • Some scientists believe that the species might’ve used its tail club for display purposes to attract mates or fight with others of its kind for territorial or mating reasons.

Apart from this, little is known about their behavior. We do have some things to share about their diet, so keep reading!

It was a herbivorous dinosaur that specialized in feeding on low-growing vegetation.

Tooth of Ankylosaurus
Tooth of Ankylosaurus (specimen AMNH 5895) in outside and inside view | Barnum Brown via Wikipedia

The teeth and beak shape of the Ankylosaurus were thought to have been well-adapted to eating fruits, too, besides fibrous and woody plants.

The species is believed to have been able to eat around 6 kilograms (13.2 pounds) of dry ferns a day. This makes 2 tonnes (2.2 short tons) a year!

That is, if the dinosaur were ectothermic. If it were endothermic, the number would become much higher – around 60 kilograms (132.2 pounds) daily and up to 20 tonnes (22 short tons) per year!

Despite the heavy amount of food, an adult Ankylosaurus likely didn’t spend much time foraging and feeding, as scientists believe it didn’t chew the food.

Some studies suggest that they might’ve been omnivorous, but little evidence supports that.

Besides this, it is thought that the species was capable of digging as well, aiming for roots and tubers.

Life Cycle

Dinosaur Ankylosaurus in the forest
Dinosaur Ankylosaurus in the forest | Orla via GettyImages

Considering that paleontologists and other field-related specialists couldn’t even outline an exact Ankylosaurus appearance, it’s not surprising that very little is known about their life cycle, reproductive means, and growth rate.

It is believed that all dinosaurs had two oviducts and reproduced by laying amniotic eggs. As such, it’s safe to suppose that they did the same.

On the other hand, it would be impossible to assume how the eggs were laid, which parent was involved in incubating the eggs, and if the newly born dinosaurs were provided parental care.

We might also assume that the baby dinosaurs were precocial because many dinosaurs were born this way.

We can only hope new fossils will be recovered soon and shed some light on the Ankylosaurus life cycle!

Evolution and History

Ankylosaurus skeleton
Ankylosaurus skeleton | leonello via GettyImages

Until 1923, when Henry Fairfield Osborn named the Ankylosauria group of dinosaurs, ankylosaurs were thought to have been members of the Stegosauria, which, at the time, included all armored dinosaurs.

They have been extensively associated with stegosaurs in terms of evolutionary history.

They split up more than 170 million years ago and are now both in the Eurypoda clade under Thyreophora. Both are believed to date from the Middle Jurassic.

The Ankylosaurus type specimen, meaning the specimen that served as a base for describing the genus, was found in 1906 in Montana’s Hall Creek Formation.

The dinosaur species, the Ankylosauridae family, and the Ankylosaurinae subfamily were formally described in 1908.

Later on, Samuel Wendell Williston stated that this prehistoric animal was, in fact, the same as those in the Stegopelta genus of struthiosaurin nodosaurid dinosaurs, but other specialists disapproved of this assumption.

The year 1901 brought significant Ankylosaurus discoveries in Canada. Scientists discovered a complete skull, mandibles, and other precious fossils in Alberta’s Scollard Formation.

In 1947, the largest Ankylosaurus skull was discovered by Charles M. Sternberg.

Today, it is closely related to the Euoplocephalus and Anodontosaurus. 

Interactions With Other Species

Ankylosaurus with Other Dinosaurs
Ankylosaurus with Other Dinosaurs | Orla via GettyImages

The Ankylosaurus is thought to have shared its environment with the following animals:

  • Neornithischians like Thescelosaurus

Dinosaurs like the Triceratops, Torosaurus, Thescelosaurus, and Pachycephalosaurus were also herbivorous, so the Ankylosaurus probably rarely confronted them.

However, combat shouldn’t be excluded if food sources are scarce. This is valid for members of the same species, as well.

The Tyrannosaurus is probably the only other dinosaur that could have preyed upon the Ankylosaurus.

Ankylosaurus and Tyrannosaurus | Orla via GettyImages

It was considered an apex predator that hunted and fed on hadrosaurs, ankylosaurs, ceratopsians, and sauropods.

However, since the body armor of Ankylosaurus is thought to have done its job well in protecting its host, the Tyrannosaurus had to put in the effort to kill an Ankylosaurus.

Some scientists even believe these apex predators exhibited cooperative pack hunting behavior if they hunted prey similar to the armored Ankylosaurus because they had effective defense adaptations.

Cultural Significance

Ankylosaurus in Jurassic World Evolution
Ankylosaurus in Jurassic World Evolution | Steamblust via Jurassic World Evolution Wiki

Ankylosaurus is thought to be the most renowned ankylosaur in popular culture. The life-size reconstruction featured in 1964 in New York City at the World’s Fair greatly contributed to its popularity.

Before that, in 1947, Rudolph Zallinger created one of the world’s most famous murals, The Age of Reptiles, renowned for depicting around 350 million years of this planet’s history.

It measured 34 meters (110 feet) and portrayed an Ankylosaurus, among many other prehistoric creatures.

These were only the earliest Ankylosaurus appearances in popular culture. Since then, it’s been featured in various movies and games, by far the most known being the universe of Jurassic World.

This creature’s connection with Jurassic World is extensive, appearing in eight movies and eleven games! It is also a notable species in ARK: Survival Evolved.

Although not all portrayals are 100% faithful to what Ankylosaurus actually looked like (which isn’t a surprise, considering that not even scientists are sure of certain specifics), these appearances brought the species to people’s attention, thus shedding light on the prehistoric fauna of the Late Cretaceous.

As for scientific research, the Ankylosaurus is still the main subject of numerous studies focusing on skull and armor analysis.

Since paleontologists haven’t yet discovered a complete Ankylosaurus skeleton, we hope the future will reveal one, subsequently helping scientists find the missing pieces of the species’ evolution, history, appearance, and behavior.


Having lived during the Late Cretaceous, 68-66 million years ago, the Ankylosaurus is now the subject of scientific research, contributing to outlining a clearer image of our world’s evolutionary history.

It was a quadrupedal herbivorous dinosaur, with its hind limbs longer than its forelimbs.

By far, the most renowned characteristic of the Ankylosaurus is its armor – the creature was covered by massive knobs and plates that extended from the neck to the tail, ending in a tail club.

Despite the fascinating details we already know about the fused lizard, many aspects of its appearance remain unknown, so we’ll be waiting for other extraordinary fossil discoveries!


Can Ankylosaurus defeat T-Rex?

The Ankylosaurus could probably defeat a T-Rex, thanks to its excellent anti-predator adaptations. Although some scientists think that the body armor the Ankylosaurus possessed wasn’t always of great help, others consider that the body shape of the Ankylosaurus alone made it difficult for predators to subdue it.

Some specialists believe that Tyrannosaurus rex specimens hunted in packs if they went after prey like the Ankylosaurus, which increased their chance of winning.

Did the Ankylosaurus eat meat?

Ankylosaurus was a herbivorous dinosaur, relying primarily on plant matter to survive. Although some studies suggest it might have been an omnivore, insufficient evidence supports this.


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