Polacanthus foxii

Last updated: May 27, 2024
Verified by: AZ Animals Staff
© kamomeen/Shutterstock.com

Polacanthus, of which no complete fossils have been found, was nearly 7 feet long and could weigh as much as 2 tons!


Polacanthus Scientific Classification

Scientific Name
Polacanthus foxii

Read our Complete Guide to Classification of Animals.

Polacanthus Conservation Status

Polacanthus Locations

Polacanthus Locations

Polacanthus Facts

Group Behavior
  • Solitary
Fun Fact
Polacanthus, of which no complete fossils have been found, was nearly 7 feet long and could weigh as much as 2 tons!
Most Distinctive Feature
Spikes all of its back
Lush forests and grasslands
Allosaurus, the Ceratosaurus, and the Megalosaurus
  • terrestrial
Spiky Herbavore that looks like "bowser"

Polacanthus Physical Characteristics

  • Yellow
  • Green
Skin Type
9 to 12 feet

View all of the Polacanthus images!

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Polacanthus was a very unique dinosaur that once roamed the Earth. This four-legged armored dinosaur lived during the Early Cretaceous period, about 125 million years ago.

Polacanthus had a spiky back that extended along its neck and tail. Its spiked armor gave it a formidable defense against predators, making it one of the most resilient members of the dinosaur family. Some say this dinosaur bears a striking resemblance to the video game character Bowser.

Scientific Name and Classification

The scientific name of the Polacanthus is Polacanthus foxii. It is classified as an ornithischian, which means it was a bird-hipped dinosaur. Its name comes from the Greek words “polo” meaning “many” and “acanth” meaning “spines.” Its fossils were first discovered in 1865 by a British geologist who showed the remains to the paleontologist Richard Owen. Owen subsequently named the newfound dinosaur Polacanthus foxii.

Who Discovered Polacanthus?

Polacanthus was discovered in 1865 by British geologist William Fox. During a visit to the Isle of Wight, he recognized the fossils as belonging to a previously unknown dinosaur species. The dinosaur was named Polacanthus foxii in his honor shortly after. It’s worth noting that naming the dinosaur in this manner goes against conventions that taxons are not generally named after the author.

Description & Size

spiked Polacanthus



was built for protection against predators.


The Polacanthus was a medium-sized armored dinosaur with an elongated body shape, a thick torso, and a long extended tail. Its strong legs were covered in spiky armor plates called osteoderms. In addition, it had thick armor plating on its back and sides, as well as spikes and horns along its neck and tail. Its head was also protected by two small horn-like points. So, to say the least, this animal was built for protection against predators.

Its short, thick legs were designed for walking on land, and it had wide feet with 4 toes helping it to grip the ground as it moved. Scientists believe that the Polacanthus was yellowish-green in color, with some darker patches on its back and tail. But this is just based on educated guesses, as only fossil specimens have been found.

Although no complete skeleton of Polacanthus has been discovered, the fossils that have been found indicate that it was a strong and agile animal.

According to the calculations from its fossils, Polacanthus was around 9 to 12 feet long (3 to 4 meters) and weighed up to 2 tons.

Diet – What Did The Polacanthus Eat?

No tooth specimens of the Polacanthus have been found, so determining the diet of the Polacanthus is difficult. But the creature had a large stomach cavity, suggesting it was an herbivore. It is thought to have eaten low-lying vegetation. Its claws were adapted for digging in the ground, indicating that it also ate roots and tubers.

Polacanthus were solitary creatures that roamed the plains in search of food. It is believed to have been an active dinosaur, despite its bulky size, capable of running and jumping. Its spiky armor would have been an effective defense against predators.

It’s worth mentioning that all of this is based on educated guesses by paleontologists who studied the fossils of the animal. As they lived 125 million years ago, we have no way of actually knowing the Polacanthus’s diet.

Habitat – When And Where It Lived

The Polacanthus lived during the Early Cretaceous period, approximately 125 to 130 million years ago, in what is now known as modern-day Europe. During this period, these regions were very different from what they are today. They were warm and humid, with plentiful vegetation, including ferns, cycads, and conifers. Scientists believe that this species was a terrestrial creature that spent all of its time on land. The Polacanthus primarily stayed in one location, eating vegetation that was abundant in its habitat.

It is believed that this species inhabited dense forests and grassy plains abundant with vegetation. The Polacanthus was capable of living in a variety of habitats and could have also been found near the shorelines of rivers, lakes, and jungles.

Threats And Predators

Paleontologists think that The Polacanthus was a solitary creature, so it is believed that the main threat to its survival would have been other carnivorous dinosaurs. As a herbivore, the Polacanthus would have been a frequent and vulnerable target of large predators like the Allosaurus, the Ceratosaurus, and the Megalosaurus.

However, it may have been difficult for predators to target the Polacanthus due to its spiky back and impenetrable shell, which acted as a defense mechanism. So, it’s possible that the larger, carnivorous dinosaurs were not as big a threat as they would have been for other herbivores. The Polcanthus’s agile legs and sharp claws would have also acted as useful defenses against attackers.

Little is known about the reproductive habits of the Polacanthus; however, it is believed that this species would have laid eggs like other dinosaurs, but there is no conclusive evidence to support this. These eggs could have been an easy target for predators, making reproduction a difficult and dangerous task.

Discoveries and Fossils – Where It Was Found

The Polacanthus was first discovered and identified by geologist William Fox during a visit to the Isle of Wight in the early 19th century. Since then, numerous Polacanthus fossils have been found in Europe. There are not many complete skeletons, but the ones that have been found provide a good indication of their anatomy and size.

Extinction – When Did It Die Out?

The Polacanthus died out at the end of the Early Cretaceous period, around 125 million years ago. The exact cause of its extinction is unknown, but as with most other dinosaurs, it may have been due to climate change or competition for resources. Unfortunately, its spiky armor, agility, and solitary lifestyle were not enough to save it from whatever event caused its demise.

Similar Animals To The Polacanthus

Polacanthus was a unique species, but it had some similarities with other animals.

  • Ankylosaurus – It is closely related to the Ankylosaurus, which was a large herbivorous dinosaur that lived during the same time period. The Ankylosaurus had long spikes and armor plates for protection, much like the Polacanthus. The two dinosaurs had similar sizes and shapes, though their spikes were slightly different.
  • Armadillo – Both animals have a protective shell that is made up of bony plates and spikes.
  • Stegosaurus – Another similar animal is the Stegosaurus, a large herbivorous dinosaur from the Jurassic period. Like Polacanthus, the Stegosaurus had spikes on its back and tail, which it used for protection. Both dinosaurs had long, sharp teeth and were herbivorous.

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About the Author

Lev is a writer at AZ Animals who primarily covers topics on animals, geography, and plants. He has been writing for more than 4 years and loves researching topics and learning new things. His three biggest loves in the world are music, travel, and animals. He has his diving license and loves sea creatures. His favorite animal in the world is the manta ray.

Polacanthus FAQs (Frequently Asked Questions) 

When was the Polacanthus alive?

The Polacanthus was a dinosaur that lived in the Cretaceous period, between 125 and 130 million years ago. It is believed to have lived in what is now modern-day Europe.

How big was the Polacanthus?

The Polacanthus was a large dinosaur, estimated to have been around 8-14 feet long and 3-5 feet tall.

Was the Polacanthus an herbivore, carnivore, or an omnivore?

The Polacanthus was an herbivorous dinosaur

What did the Polacanthus eat?

It is believed that the Polacanthus fed on ferns, palms, and cycads that grew in the tropical environment during its time.

What made the Polacanthus extinct?

The exact cause of the Polacanthus extinction is unknown, but many paleontologists believe it was due to a combination of factors. These include climate change, competition with other herbivorous dinosaurs, and habitat destruction. Additionally, some researchers suggest that meteorite impacts may have caused its extinction as well.

Was the Polocanthus related to other animals?

Though not directly related, the Polacanthus shares some characteristics with modern-day armadillos and the Ankylosaurus, a large herbivorous dinosaur from the same period.

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  1. ABCDino / Accessed December 7, 2022
  2. DinoWight / Accessed December 7, 2022