25 Facts About The Mosasaurus For Kids

The mosasaurus was an aquatic reptile that lived during the Cretaceous period. It was one of the largest marine predators of its time, and is believed to have been up to 50 feet long.

Although it has been known for over 100 years it became famous in the ending of the jurassic World movie for saving Claire and Owen (and the T-Rex) and dragging the Indominus Rex into the lagoon at Jurassic World.

Mosasaurus was a large marine reptile that lived during the Late Cretaceous period. (101 – 66 million years ago. It could grow to over 45 ft long, could weigh over 28,000 lbs and had over 50 cone shaped teeth in its 6 ft jaws. Mosasaurus was carnivorous and hunted fish, squid, and other marine reptiles.

We take a look at this dinosaur…and look at 25 facts about it including the first one is it a dinosaur? which we will answer right here.


Mosasaurus was not by scientific definition a dinosaur, it was a marine reptile that lived in the era of the dinosaurs. However, to casual observes it certainly checks a lot of those dinosaur boxes!

  • Massive in size – check
  • loads of teeth – check
  • extinct – check ( thankfully!!)
  • Lived 65 million years ago – check

So if it wasn’t a dinosaur what exactly was this massive ocean predator? We answer this and give you other facts in our list of mosasaurus facts for kids below.

We also have a printable fact sheet for you to collect on this page and you can collect this with the others we have on our fact pages around the site.

facts about Mosasaurus for kids

Quick Mosasaurs Facts

The Mosasaurus was certainly big, however the estimates vary from 36 feet to 59 feet long.

The name Mosasaurus, means “Lizard of the Meuse River

Mosasaurus has between 40 to 50 sharp, cone-shaped teeth.

Some were just 3 feet long (1 metre) and others are estimated to be up to 59 feet long! (almost 20 metres)

On average Mosasaurus teeth were about 2-3 inches long, and the a large tooth would be over 4 inches long.

Mosasaurus is quite easy to say it is Moss – a – Saw – Rus

dinosaur facts for kids

25 facts about the Mosasaurus

1. The mosasaurus had a short, wide body and a long, thin tail. It was a powerful swimmer and could hold its breath for extended periods of time.

2. The mosasaurus had a hinged lower jaw, which allowed it to open its mouth very wide. This made it an effective predator and scavenger.Its teeth were conical and serrated, perfect for seizing and slicing through prey.

3. The Mosasaurus was certainly big, however the estimates vary from 36 feet to 59 feet long. The have measured this by estimating that the body of the mosasaurus was 7-10 times longer than the skulls they have found.

Sometime scientists have to take educated guesses just due to the lack of information.

4. It is believed that the mosasaurus gave birth to live young, rather than laying eggs. They were very adapted to ocean life so the general thought is, even though they breathed air, they didn’t go on to beaches and lay eggs like turtles do now.

5. The first mosasaurus fossils were discovered in 1764. That makes this one of the early dinosaurs to be discovered. The fossils were found in Maastricht in the Netherlands. At the time people thought it was maybe a crocodile, a large lizard or even a whale.

We have 20 of these Mosasaurus Facts for you to download print and Collect if you want below.

6. The mosasaurus was alive during the Late Cretaceous period, around 88 to 65 million years ago, swimming in the oceans. It seems it was quite widespread, as fossils have been discovered in multiple locations around the world.

7. The name Mosasaurus, means “Lizard of the Meuse River”. Mosa means meuse in latin, and saurus means lizard in greek. the fossils of the mosasaurus were first found next to this river in the Netherlands in a limestone quarry in 1764.

8. There are quite a few different species of Mosasaur, some were just 3 feet long (1 metre) and others are estimated to be up to 59 feet long! (almost 20 metres) The mosasaurus was the largest and most advanced member of this family.

9. Mosasaurs were closely related to monitor lizards and alligators, which are still alive today.

10. Mosasaurus has between 40 to 50 sharp, cone-shaped teeth that were perfect for grabbing and holding prey.

11. Mosasaurs had a hinged lower jaw, which allowed them to open their mouth very wide, this was by design as most prey would have been swallowed whole, or ripped and shook into pieces that were able to be swallowed whole.

12. Mosasaurus was very widespread. fossil remains have been found all over the world including in: Africa, europe, North America, South America and even Antarctica!

printable dinosaur coloring pages

Mosasaurs and Pterosaur Printable coloring pages.

13. The mosasaurus in Jurassic world was really much larger than they would have been in real life, and there is little chance it would have been big enough to pull in a dinosaur larger than a T-Rex into the lagoon. However, it was an awesome ending to the indominus Rex.

14. The mosasaurus in Jurassic world had a lot of dramatic license added to it. When we first see it its mouth is longer than a great white shark, which can be 5-6 meters long. this would make the mosausus up to 60 metres in the movie.

Just for reference this would have made it 2 times longer than a blue whale, even if the shark as smaller it would still be about the same size as a blue whale. So “maybe it depended on what type of mosasaurus they cooked up in that lab”

facts about Mosasaurus for kids

15. The mosasaurus would have been an opportunistic predator, and remains of sea birds, fish, marine reptiles, other mosasaurus, ammonites and almost anything else that swims or wandered near water has been found in its fossilized stomachs.

16. Mosasaurus had plenty of teeth in it long mouth but they were not quite as large as other large carnivorous dinosaurs on lange. On average they were about 2-3 inches long, and the a large tooth would be over 4 inches long.

You can check out the link below if you are a parent or teacher and want to get a few for your children or students for gifts or prizes.

17. As they had so many teeth, and they were very wide spread around the world it is one of the more accessible fossils people can collect. They can be bought for just a few dollars for the small ones. You can check out some on the link below.

18. The largest of the mosasaurus could possibly weigh upwards of 28,000 lbs (14,000kg) according to wikipedia. However, scientists are still unsure of exactly how “bulky” a mosasaurus was and most data relates to their length not weight.

19. Even though Mosasaurus breathed air and was potentially similar to monitor lizards (or snakes) it was not able to move on land. its limbs had evolved into flippers and would not have been able to get around outside of water using them…. thankfully!


20. Mosasaurus loved to eat Ammonites it seems. Many shells of this large mollusc have been found with bite marks on both sides! Ammonites are another fossil that are pretty cheap to collect as well.

21. Scientists research has shown that the Mosasaurus lived close to the top of the water, it is unlikely it dived deep to hunt.

22. Dinosaur names can be hard to say. The word ‘Mosasaurus’ has 4 syllables and you pronounce it like this as moss-a-saw-rus

Moss – a – Saw – Rus

23. Once they got older they were the apex predator of their time. An Apex predator is a predator that is top of the food chain, where nothing else eats it. Like lions and Orca (Killer Whales) today.

24. As they are no fossils of Mosasaurs found more recently than 65 million years ago, which scientists suggest means this large predator was caught up with the aftermath of the Asteroid Impact that caused the extinction of most land based life.

25. The Mosasaurus may have been first discovered in 1764 ( when it must have looked like a huge sea monster) It didnt get its name, or be classified officially until almost 60 years later when in 1822 William Daniel Conybeare gave it the name Mosasaurus which as we explained above, is because it was discovered near the Meuse river in the Netherlands


There are 25 facts about the mosaurus here, but there is loads more to know about one of the fiercest of aquatic dinosaurs. If you have any facts you want to include you can leave them in the comments and we will add them into the article. If you want to use your name we can credit you next to the fact as well!

You can check out our other dinosaur facts on the pages linked in and below to learn more about dinosaurs.

We also have printables here which you can access, or purchase to help keep the site going.

Some of My Dinosaur Resource Recommendations for Home and School.

Thanks for taking the time to read our facts and questions articles, as a teacher myself i have struggled to find resources in one place and that is why this website was born. I simply love teaching students about dinosaurs both in my role as a language and General Studies teacher. However there is sometimes a need for something more concrete than a printout (as useful as we think ours are! )

There is something awesome about the feeling of awe that these amazing creatures instil in our children and students. To further help you, and potentially me, i have included a few resources below that i have found to be incredibly successful when explaining dinosaurs to children, these range form books and resources, to toys fossils and dinosaur figures.

Sometimes having something tactile to touch in those tiny hands help to focus and cement learning and develop those big brains! Hope they are helpful too.

Dinosaur Books and Readers

There are of course hundreds of excellent, and not so excellent books on Dinosaurs for Children out there. So rather than, yet, go into huge detail. I will highlight the ones I love to use with my students from ages 6 to 10. We have include AR in these as well. ( nothing quite like a moving dinosaur in front of you!

Fossil Sets

I cant say how great these are to use in a classroom while reading with a group. the chance to read about a dinosaur and then touch a real piece is simply great. I have a selection ( self confessed dinosaur geek) but a cheap set of 10 or so will do the trick just as well. Dinosaur poop is great as well!!! i pass it round and ask them to guess what it is first!

Dinosaur Figures

I actually use realia in a lot of classes especially with animals and dinosaurs, and figures help to show the kind of animal we are reading about. It is possible to spend hundreds of dollars on dinosaur figures but ther eis no need, either as a teacher or a parent. The set below and similar we have used to help students picture dinosaurs to great effect.





Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *