Discover the 23-Foot, Gigantic Ancient Crocodile With Fins

Written by Lisha Pace
Updated: October 2, 2022
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Key Points:

  • With jaws capable of biting through a mid-sized car, Liopleurodon’s bite may have been even stronger than the bite of the Tyrannosaurus.
  • Like sharks, the Liopleurodon had powerful, front facing nostrils. They might have used their highly advanced sense of smell to detect the blood of fresh kills by other predators.
  • Liopleurodon lived from the Callovian Stage of the Middle Jurassic and possibly as early as the Cretaceous period. They were most likely found in the oceans surrounding Europe.
  • The K-T event (Cretaceous-Tertiary extinction event) could have caused the extinction of the Liopleurodon. This happened 65.5 million years ago.

Since appearing on BBC’s Walking With Dinosaurs series, the Liopleurodon (Lie-oh-ploor-oh-don) doesn’t need much introduction. However, that series also strengthened the misconception that this marine reptile was a dinosaur. It wasn’t. Dinosaurs didn’t live in water and the Liopleurodon, which belonged to the Pliosaurs of the Mesozoic Era, was one of the most powerful carnivores that ever existed on the planet. If it is compared to a modern-day animal, it would have to be with the crocodile since their snouts look similar.

Do you know that some scientists believed that the Liopleurodon’s bite might even have been stronger than the Tyrannosaurus’s bite? This Pliosaur could have munched through a mid-sized car in seconds. That was how powerful its jaw and teeth were. Speaking of jaws and teeth, the Liopleurodon’s composed one-fifth of its body length.

Another common misconception about Liopleurodon that was proposed by the TV series was that it measured up to 25 meters. In reality, this ancient aquatic reptile only grew in adult size up to seven meters. It was nowhere near the gargantuan size perpetuated by the series and other opinions.

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The decision of the makers of the series to depict the Liopleurodon much larger than life is up to debate. However, the dramatic scenes in Walking with Dinosaurs increased public engagement and interest about these less famous ancient repitles.

Liopleurodon, in Summary

AgeCallovian, Middle Jurassic
LocationEngland (Peterborough, Bedfordshire, Cambridgeshire), France, and Chile; possible Argentina and Mexico
Named byHenri-Émile Sauvage, 1873
SizeOne complete specimen is 6.39 meters long, but evidence points to the species possibly growing up to 7.5 meters

Description and Size

There are many opinions about Liopleurodon’s size. People first encountered this ancient marine reptile in that BBC TV series. However, that series also perpetuated the idea that the Liopleurodon grew to 25 meters. Records showed that it only grew up to the adult size of 7 meters. Another opinion said a discovered fossil of a juvenile Liopleurodon proved it could have grown more than 18 meters.

Liopleurodon had a huge head compared to the rest of its body. Its jaw alone comprised one-fifth of its body’s length. Its skull supposedly measured one and a half meters long. If a Liopleurodon had that skull size, it means an adult measured more than seven and a half meters long based on the principle that the jaw and skull were one-fifth of its length.

This ancient aquatic reptile also had a powerful bite. Its teeth were buried 20 centimeters into its jaw, so it could grab and munch on prey with ease. Similar to the pliosaur’s limb arrangement, the Liopleurodon had four flippers on the side. These flippers provided excellent acceleration when they needed to swim after their prey.

Its nostrils were forward-facing on the snout. This suggests that the marine reptile had a highly developed sense of smell. It is said that it was able to find its prey despite being out of visual range. The Liopleurodon might have used this highly advanced sense of smell to detect the blood of fresh kills by other predators. This is also what sharks do today.

Although the Liopleurodon lived underwater, they could not breathe underwater since they had lungs and no gills. Instead, they needed to surface for air, similar to whales, dolphins, and seals.

3d rendered illustration of a Liopleurodon

Evidence points to Liopleurodon growing up to 7.5 meters long.

©3d rendered illustration of a Liopleurodon/

What Did Liopleurodon Eat?

Scientists believed the Liopleurodon was the apex predator of the marine ecosystem during its time. It constantly fed on fish, squids, and other smaller marine reptiles with its powerful bite and sleek swimming skills.

The ancient marine animal was a carnivore, feeding mainly on Kimmerosaurus and other prehistoric marine reptiles. It supposedly had an ambush-style of hunting, using its powerful thrust to catch and attack prey. This is supported by the Liopleurodon being a fast swimmer, though not as fast as Great White Sharks.

Its four broad, flat, and long flippers were enough to thrust itself through the water at considerable speed. And when its prey tried to escape, the Liopleurodon could accelerate fast enough to catch it.


Liopleurodon lived from the Callovian Stage of the Middle Jurassic and possibly as early as the Cretaceous period. Some experts believed the species could have also survived until the Kimmeridgian stage of the Late Jurassic Period. This marine reptile most likely lived in the oceans surrounding Europe since most of its fossils were found near Great Britain, France, and Germany.

But since there was a supercontinent then, it was also possible that the Liopleurodon lived all over the planet. That was why some fossils were also purportedly found in Argentina and Mexico.

3D illustration of Liopleurodon hunting

Liopleurodon had four broad, flat, long flippers that allowed it to thrust itself through the water at considerable speed.

©Michael Rosskothen/

Threats and Predators

It is hard to imagine that there was a bigger predator than the Liopleurodon during its time. It was called an apex predator for good reason. When it hunted, it almost always got its prey because of its flippers and powerful bite. Its teeth were embedded with a depth of 20 centimeters down its jaw, making it one of the scariest marine reptiles.

As a predator, the Liopleurodon was sleek and vicious. Many scientists believed the Liopleurodon was an ambush predator. It attacked rapidly, surprising its prey with its brute force. With its flippers, it could accelerate quickly, catching prey and subsequently munching on them.

The only possible threat to the Liopleurodon was the evolution of the Mosasaurs, another extinct aquatic reptile that measured up to 40 meters long. Even if it had been extinct for millions of years, the Mosasaurus was the largest animal ever lived.

Discoveries and Fossils

H.E. Sauvage found the first fossils of Liopleurodon in a town in France. The first known fossils were three pieces of teeth three inches long each. This gave rise to the name given to this species — Liopleurodon, pronounced LEE-oh-PLOOR-oh-don. The name translates from Greek as “smooth-sided teeth.”

Most of the fossils of this marine species were found in England and France. It is also possible that some fossils reached Russia and as far as South America owing to the arrangement of the continents during the Jurassic period. In particular, evidence that this predator existed was discovered in Peterborough, Bedfordshire, and Cambridgeshire. There were also fossils in France near Boulogne and Chile.


There is very little known about the reproduction system of the Liopleurodon. What scientists understand is that they could not leave the sea. They probably gave birth to their offspring alive rather than lay eggs. To do that, they would need to go to shallow waters and give birth there. Like other large marine species, the Liopleurodon gave birth to one offspring at a time. A long gestation period was also possible.


The Liopleurodon was deadly, but it was no match for the species that came after it. The evolution of larger marine reptiles spelled the end for the Liopleurodon. At the start of the Cretaceous period, more underwater animals developed. One of these was the Mosasaurus. These are larger, sleeker, and more vicious marine animals.

The K-T event (Cretaceous-Tertiary extinction event) could have also caused the extinction of the Liopleurodon. This happened 65.5 million years ago. This was also the reason dinosaurs went extinct. For many years, paleontologists believed the event resulted from climate and geological changes that cut the dinosaurs’ food supply.

However, discovering a layer of iridium led many scientists to believe a meteor, comet, or asteroid caused the extinction. This belief was reinforced by the discovery of the Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula in the 1990s. Further inspection of the crater revealed it was as old as the K-T extinction.

3d rendered illustration of a Liopleurodon on a white background

Since Liopleurodon had no gills, it had to surface to breathe oxygen, much like modern dolphins and seals.


Similar Animals to Liopleurodon

There aren’t many similar modern animals to the Liopleurodon. However, it shares characteristics with some of these animals:

  • Pliosaurus: The pliosaurs went extinct 65 million years ago. It had four flippers that it used to swim across the oceans of western Europe. It lived during the Late Jurassic 150 to 145 million years ago. It grew to 40 feet long and weighed around 25 to 30 tons. Aside from its flippers, it also had a long-snouted head and short neck.
  • Mosasaurus: This was the reason the Liopleurodon went extinct. The presence of a larger predator led to the demise of the species. The Mosasaurus was around 50 feet long and 15 tons in weight. Like the Liopleurodon, it needed to come up for air.
  • Great White Shark: The Liopleurodon was as fast as the Great White Shark, though not as deadly. An adult can weigh as much as 1,100 kilograms. The female adult has a length of 4.5 to 6.4 meters, while the male adult was between 3.4 and 4.1 meters.
  • Beluga Whale: Unlike the Liopleurodon, Beluga Whales are friendly. These are gentle giants. They swim in groups of 10, but thousands of Beluga Whales can come together during migration. The life span of the Beluga Whales is around 35 to 50 years. Even at a massive 1,400 kilograms, these whales are the smallest species of the whale.

Up Next…

The photo featured at the top of this post is © Daniel Eskridge/

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About the Author

After a career of working to provide opportunities for local communities to experience and create art, I am enjoying having time to write about two of my favorite things - nature and animals. Half of my life is spent outdoors, usually with my husband and sweet little fourteen year old dog. We love to take walks by the lake and take photos of the animals we meet including: otters, ospreys, Canadian geese, ducks and nesting bald eagles. I also enjoy reading, discovering books to add to my library, collecting and playing vinyl, and listening to my son's music.

FAQs (Frequently Asked Questions) 

When did Lioplurodon live?

The Liopleurodon lived 166 to 155 million years ago, in the middle of the Jurassic period.

How big was the Liopleurodon?

There are varying pieces of information about the Liopleurodon’s size and weight. However, scientists believe the biggest Liopleurodon was at 7.5 meters.

What did Liopleurodon eat?

Liopleurodon was a carnivore that feasted on fish, squids, and other smaller marine reptiles.

What were the distinguishing features of Liopleurodon?

The most distinguishable features of the Liopleurodon were its size and the four flippers that helped it accelerate.

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