Tylosaurus Proriger, commonly known as Tylosaurus, was a massive mosasaur that existed near the final phase of the Cretaceous era. Being a particularly vicious creature, it has been proposed that Tylosaurus used its specialized and frequently scarred snout as a means of defense against other creatures of its sort over territorial disputes. 

That has ensured its regular inclusion in pop culture. Tylosaurus used its lengthy robust, laterally flat tail, similar to mosasaurs’, to propel across the ocean and attack its victims with flashes of propulsion. This slender torso adorned with lizard-like plates was propelled via the paddle-like limbs.


Tylosaurus was the biggest of the aquatic reptiles known as mosasaurs, growing to a length of around 30-40 ft. Even if the body wasn’t completely fusiform such as that of a fish, it was nonetheless improved in order to be as hydrodynamic as necessary. While indeed it was a relatively large creature when observed from the sides, yet when seen from a straight head, it should have appeared to be quite a narrow cross-section. 

The body of Tylosaurus was highly hydrodynamic, making them fast and efficient swimmers
The body of Tylosaurus was highly hydrodynamic, making them fast and efficient swimmers

This greatly reduced the degree of friction Tylosaurus encountered as it moved through the water, in addition to its piercing, sloped cranium. Furthermore, the correspondingly thinner flippers compared to pliosaurs were employed less for paddling and more for maneuvering, reducing hydro-drag.


Because of its massive size, Tylosaurus was able to become an apex predator with ease, thus ensuring that nothing was off-limits. They were known to have eaten fish, sharks, some flightless birds, enormous plesiosaurs, along with other mosasaurs. Even though Tylosaurus had strong jaws and huge teeth, it’s possible that these weren’t its main methods of striking in the conventional sense. 

The jaws’ most forward regions have severely reduced tooth density to the extent of just being toothless. Its head is additionally strengthened, rendering it more robust compared to other marine reptiles. 

Tylosaurus was the apex predator of its habitat, consuming birds, plesiosaurs, and with other mosasaurs
Tylosaurus was the apex predator of its habitat, consuming birds, plesiosaurs, and with other mosasaurs

Moreover, some Tylosaurus snouts exhibit stress deformation that might have resulted from a jarring collision. All of these indicate that Tylosaurus rammed victims at great speeds employing extreme force. One such blow would certainly not harm the victim directly, but it might very quickly paralyze it, causing it to drift helplessly in the water, awaiting the final bite.


Despite breathing air, Tylosaurus was well suited to live in the warmer, shallow inland seas that have been typical at the near-end of the Cretaceous era. In the Western Interior body of water, which previously inundated Northern America, Tylosaurus was the dominating species. Today’s United States of America and Canada were once part of the territory that the seaway went across.


Even though it’s not fully understood the Tylosaurus’ reproductive system, researching its extant counterparts can provide insights into this interesting animal’s life cycle. The Tylosaurus is believed to have propagated comparably to contemporary lizards.  Females would deposit their eggs in hot, sandy regions, in which the sunlight could subsequently incubate them. The newborns would’ve been left to fend for themselves in the hostile environment after they hatched.


Tylosaurus had no natural enemies to threaten them. However, they were prone to being vulnerable at the juvenile stage since newborns are left to defend themselves. It’s theorized that the main threat to Tylosaurus was other members of its species, where the bigger specimen attacks and eats the smaller ones. 

They would most commonly bite the head of the other, as supported by fossil evidence. While the motive of such attacks is alleged to be in the context of courtship, it is most likely a way to assert dominance over one another.

Facts about the Tylosaurus

  1. The largest Tylosaurus measured a length of 39 ft and weighed around 12,000 lbs.
  2. Tylosaurus lived around 90 million years ago during the Cretaceous era.
  3. The very first Tylosaurus fossil, consisting of a cranium and vertebrae, was found in Kansas in 1868.
  4. Tylosaurus anatomy allowed them to swim at a speed of 30 mph while maintaining efficiency.
  5. Tylosaurus fins were exclusively for steering and not propulsion.


Why did Tylosaurus go extinct?

Tylosaurus eventually went extinct during the Cretaceous mass extinction at the peak of the age, despite having developed to withstand the majority of dangers. All the non-avian dinosaurs were killed off by this catastrophe about 65 million years ago.

What distinguishes Tylosaurus from Mosasaurus?

There are two distinct species of marine reptiles in the Mosasauridea genus: Tylosaurus and Mosasaurus. They are referred to as mosasaurs as just a group. The Tylosaurus did not, however, possess teeth on its bone rostrum or around the tip of its nose like all other mosasaurs did.

Was the Tylosaurus a type of dinosaur?

You might be misled by the name of the Tylosaurus, and it’s a common misconception but they weren’t a dinosaur species as they don’t check the criteria to be designated as one. The Natural History Museum at the University of Kansas is home to the mosasaur fossils and many other species that are from the Cretaceous era.

What was Tylosaurus like?

The Tylosaurus was an open-ocean species that frequently gobbled down the majority of the active species in its vicinity. They frequently defended themself from attackers like mosasaurs by swimming in clusters. They were considered to be one of the deadliest creatures of the Late Cretaceous era.

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