"The Mosasaurus was thought to have hunted near the surface of the water, where it preyed on anything it could sink its teeth into, including turtles, large fish, even smaller mosasaurs." -- Sarah, the Mosasaurus feeding show announcer.

Mosasaurus was a genus of large aquatic carnivore from the Late Cretaceous about 70-65 million years ago. Mosasaurus gave its name to a group of marine lizards, the mosasaurs.

Name Meaning

Mosasaurus (pronunciation: "moh-suh-saw-rus") means "Lizard of the Meuse River."  'Mosa' stands for the Meuse river in Holland, the location where mosasaurs were first described. 'Saur' (Sauros) is greek for lizard.


Mosasaurs were powerful swimmers that had a long, streamlined body. The long head had very pointed, powerful jaws with many sharp teeth. Mosasaurs had four short, paddle-like limbs adapted to life in the water. A long tail, perhaps finned, completed its serpentine body. 

Physical Appearance and Size 

Mosasaurs were sleek, streamlined, and were mildly fast. They had flipper like paddles for arms and legs. They propelled themselves by moving the back of their bodies and tails in a side to side motion. Mosasaurus were also covered in smooth scales which were probably dark on the back and light on the underbelly.

In reality, the smallest mosasaur was about 9.8 feet long. This species, Carinodens belgicus, was suited for shallow water. It had bulbous teeth which were likely used for cracking open mollusks and sea urchins. Clidastes were 10 feet long and from Late Cretaceous North America. Mosasaurs were generally much larger. The longest and largest mosasaur is Mosasaurus.    

Platycarpus and Dallasaurus were smaller genera. They reached 10-20 feet long. Platycarpus lived 85-80 mya and was the most common mosasaur in North America. It was generally 14 feet long, shorter in the skull than other mosasaurs, and likely ate shellfish in the shallow sea that covered the middle of North America.   

Other mosasaurs were predominantly large. Prognathodon reached about 33 feet long. Mosasaurus could reach 40 feet long and is estimated to have weighed 15 tons. The closely related Tylosaurus could exceed Mosasaurus in length, but had a proportionally leaner build and thus similar mass. Mosasaurus was from the Late Cretaceous and lived 70-65 mya. It is recognized for a blunt head that resembles an alligator and the tail fin that was present in some mosasaurs. These large reptiles were apex predators of their time.   

In reality, the Mosasaurus was able to reach full size of 50 feet long and weigh over 30,000 lbs. In Jurassic World, it measures at least 25.9 meters long or 84 feet long while website the Mosasaurus can reach up to 60 feet long and weight about 5 tons.



A single Mosasaurus was created for the new Jurassic World as an amusement for viewers as a feeding show. She is the only one in Jurassic World and is the second cloned Aquatic animal, first being Tylosaurus. They added a saltwater crocodile and a monitor lizard to complete the missing code in it's DNA.


Jurassic World (2015)

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Mosasaurus devouring a dead shark.

The mosasaur's feeding show displayed the Mosasaurus eating a shark, identified as a great white shark. This show occurred every two hours. The Mosasaur lived in a 3 million gallon pool of water located near the Main Street known as the Jurassic World Lagoon. Visitors could also view her through an aquarium below the lagoon known as the Underwater Observatory to see her.
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Mosasaur eats the rest of the shark

Jurassic World Incident

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She swallowed a Pteranodon after the flying reptiles of the aviary were released, taking the British assistant Zara Young with her.

At the end of the battle between the Indominus rex, Rexy the T. rex and Blue the Velociraptor, the Mosasaurus beached herself to catch the hybrid in her powerful jaws and dragged it to the bottom of the lagoon, thus killing it by drowning the hybrid, saving the park and avenging Blue's sisters (Delta and Echo).

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Saving Jurassic World from its biggest threat

Jurassic World Fallen Kingdom

It is revealed that the individual Mosasaurus seen in Jurassic World has survived the years it has spent on Isla Nublar. It was thought to be dead when the submarine went in to collect a sample of what was left of Indominus rex. The Mosasaurus then ate the sub, along with a mercenary trying to escape on a helicopter, and when the gates were left open, it escaped the lagoon and swam into the ocean. It was last seen trying to eat surfers off of a coast.


She rivals the sauropods in size and is one of the strongest of all InGen creations though mostly underwater.

Strength and Combat

The Mosasaurus is a very large powerful aquatic reptile that was shown to be strong enough to drag the struggling Indominus rex into the water.

She has very powerful jaw strength with a bite force of 33,000 pounds, which was at least as powerful as the Tyrannosaurus. She uses her powerful jaw strength to kill a Pteranodon and finally drown the Indominus rex.

Though judging by the body their main attacking its like T-rex with its head and powerful jaws that they can take down many prey that was proven by Indominus rex.


In reality, Mosasaurus fed on such prey as large fish, plesiosaurs, seabirds, sharks and other mosasaurs. It would prey on pterosaurs and some dinosaurs that fell into the water.

Mosasaurus showing her hunting style

In Jurassic World, it is fed by the volunteers with dead Great White Sharks and jumps out of the water to feed. Mosasaurus were probably ambush hunters and in the film seem to be patient predators, able to wait until the Pteranodon was low enough over the lagoon or until the railing had been knocked away and the Indominus rex was within reach.

In reality, Mosasaurus probably rarely ventured close to shore for risk of getting stuck and then suffocating under its own weight, but Jurassic World's Mosasaurus partially beached herself to grab the Indominus rex.


Although Mosasaurus lived their lives in the seas as able to stay underwater for long period of time, but they still needed to breathe air and had to surface periodically in order to breathe. Their ancestors dwelled in water as early crocodiles.  

Durable And Stamina

The Mosasaurus seems to have thick skin judging by Indominus Rex trying to use her claws on her foot to scratch the Mosasaurus back to no avail.

Her stamina must be very high as it was needed to sustain long periods swimming.


  • Mosasaurus is the earliest genus known to science featured in the franchise. The first Mosasaurus fossil was discovered and named in the 1770s, almost a full one hundred years before the first dinosaur, Iguanodon, were recognized and named.
  • Average sized Mosasaurus can reach 40 ft long, but the biggest found was approximately forty five feet long, meaning they could probably have reached sixty feet in length with freak individuals. The Jurassic World's Mosasaurus was seventy-two feet long; this was probably due to the gaps in its DNA being filled with the DNA of modern animals. Despite her massive size however, the Jurassic World Mosasaurus is actually still out sized by extinct Cenozoic super predators such as the massive shark, Carcharocles megalodon (29-30 tons), predatory whale Livyatan melvillei (30-40 tons); and the modern sperm whale (50-60tons), however it was most likely longer, then the two Prehistoric predators, like the real life Mosasaurus which can measure a meter long than both Livyatan and Megalodon.
  • The Mosasaurus was initially going to appear in Jurassic Park 3, featured in the early draft that was much different than the final film. However because they had been cut from the previous film's climax, the focus was instead shifted to the Pteranodon.
  • Colin Trevorrow came up with the idea of featuring Mosasaurus, the film's main marine reptile which you see in the trailer. He pitched the idea to Spielberg of having the Mosasaurus feed on a shark in front of bleachers filled with park guests. Spielberg loved the idea of the Mosasaurus eating the shark but suggested that when the animal grabs the shark that the whole bleacher section would slide down using a hydraulic system so that the audience will be able to see the Mosasaurus feeding underwater. The moment where the Mosasaurus soaked 200 extras in the bleacher section was Colin Trevorrow's favorite moment of shooting. 
  • Some fans have nicknamed the Mosasaurus "Shygal" because she was described as "shy" by Sarah, the feeding show announcer, others have chosen "Mosy".
  • Mosy is the last of her kind along with Blue and Rexy.
  • The captive mosasaur in Jurassic World is the only surviving member of her genus and her family.
  • It has been suggested that another facility mass-produces the sharks the Mosasaurus eats via cloning (possibly to avoid lawsuits or accusations of animal abuse, since great white sharks are endangered).
  • The Mosasaurus' bite scene has been changed three times in the trailer.
  • In the trailer the Mosasaurus eye was seen but was cut and not seen in Jurassic World: Fallen Kingdom.

The changes the bite scene went through.