In Jurassic World, we meet a mosasaurus. We see it again in Jurassic World: Fallen Kingdom, for instance in this trailer (at 1:53).

Jurassic World: Fallen Kingdom, Mosasaurus

It seems quite a bit larger than the maximum estimate of the largest actual mosasaurus, which is about 17m.

How large exactly is it in the film? And has it grown between Jurassic World and Jurassic World: Fallen Kingdom?

  • 2
    16-26m depending on the source, trying to track a credible one though.
    – TheLethalCarrot
    Jun 11, 2018 at 11:03
  • 1
    I found one picture on wikia (don't know how reliable it is) which puts the mosasaurus at around 26m long. Here's the link: jurassicpark.wikia.com/wiki/…
    – Shreedhar
    Jun 11, 2018 at 12:30
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    I believe the correct term is "bloody enormous".
    – Valorum
    Jun 11, 2018 at 17:23
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    On the subject of its unrealistic size, I imagine that in the absence of any sort of predation, given reliable food supplies, perhaps the Mosasaurus simply never stops growing. The fossil record simply doesn't account for those rare individuals that achieve leviathan size. That and Dr Wu explicitly states that they designed the creatures to be more public-friendly, people want to see a monster the size of two blue whales, they get a monster the size of two blue whales, "realism" be damned Jun 12, 2018 at 9:29
  • 1
    I was entirely guessing on the first point :P Nice to be confirmed as partially correct. Jun 12, 2018 at 11:16

4 Answers 4


Their animation director, Glen Macintosh actually discussed this discrepancy in a recent interview with Engineering & Technology magazine:

[...] the Mosasaur originally started out as like 60ft long and when it came out of the water it just didn’t look imposing. So we would start scaling it up… Ultimately the Mosasaur came in at about 110-120ft long, twice as long as it should have been and about the size of a blue whale.

The rest of the interview can be found here.

† about 33.5–36.6m.

  • 7
    That is 33.5 - 36.6 meters Jun 12, 2018 at 7:01
  • 3
    Is not a 60ft apex predator imposing?! Let's put this guy with in a tank with a 10ft crocodile and see what he thinks about it
    – jean
    Jun 12, 2018 at 13:09
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    @jean good point :-) but it’s a monster movie...people like their monsters huge (see Legendary’s Godzilla, for example)
    – DeltaIV
    Jul 5, 2018 at 14:18

If the shark it eats in Jurassic World is a Great White, there's no way the mosasaur is 18 meters long: it must be considerably longer than a Blue Whale. This site makes a case for it being 50 m long, assuming the shark is a Great White:

enter image description here

A lot of people then complained that the shark was not a Great White (though it looks remarkably like one), thus the same site touched on this point again, providing a set of plausible pictures depending on the size of the shark:

enter image description here

Another counterpoint: we know that, in absence of sharks, it fancies snacking on Indominus Rex enter image description hereenter image description here Now, this picture doesn't show it very well, but it's clear from the movie that the head of the Mosasaur is much bigger than that of Indominus Rex, which http://www.jurassicworld.com/ states to be 15 m long. Thus, no way it's just 3 m longer.

Finally, from the trailer you show, it's obvious that only the head is considerably longer than a surfboard (say, 3 surfboards?), and unlike plesiosaurs, with which they're often confused, mosasaurs' body plan included an head which was much shorter than the body + tail, so no way this thing is 18 m long, even though that's the official length according to http://www.jurassicworld.com/.

The mosasaur is clearly as long as the director needs it to be, in different scenes.

  • 4
    Great Whites don't show a huge variation in physiology as they grow: without a specific reference, you'd be hard pressed (from a distance) seeing the difference between a 3 meter long subadult Great White and a 6 meter long big female. Also, the majority of adult males are only 3-4 meters long, and females 4.9 to 4.9 meters. A 6 meter long shark would rare and massive: the largest confirmed shark was a 6.1 meter female caught in 1988. Jun 11, 2018 at 16:35
  • @KeithMorrison a fair point, but 1) the second picture considers a shark 5 mt long, not 6, and we still exceed the 30 mt 2) in the first picture (the one where the mosasaur is chomping the fishy) the head of the mosasaur is clearly longer than the shark. Now, no mosasaur skull ever found is longer than 2 meters (I can't find a reference right now, you'll have to trust me on this), and they got up to 17 mt long. Thus, even a 4 mt shark would make our mosasaur at least twice as long as "real" ones. 18 mt is an untenable size.
    – DeltaIV
    Jun 11, 2018 at 18:12
  • @KeithMorrison btw, considering a 4 mt shark I get a size of 34 mt which is basically the same as the one in the accepted answer!
    – DeltaIV
    Jun 11, 2018 at 18:14
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    "The mosasaur is clearly as long as the director needs it to be, in different scenes." Heh - good one. Everyone here would know producer Spielberg's famous quote about continuity: "Fuck continuity" :)
    – Fattie
    Jun 11, 2018 at 23:03
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    heh right. The size of the head is measured in "movie meters". :) Even in the pre-computer era, films from the King Kong / Godzilla era had "un-strict" measurements. it's just how filmmakers work. It's like drawing a cartoon.
    – Fattie
    Jun 12, 2018 at 12:25

The official website states that they are:

9.8 Ft. Tall / 55 Ft. Long

Which is roughly 16.7 meters.

The jurassicworld.com site has been "taken over" by the Dinosaur Protection Group at http://islanublar.jurassicworld.com/. Though this website is linked from the official site it claims that the mosasaurus is 18 meters long.

There are a few sites that all claim different sizes (just see the size estimates on the wikia) but the Universal Pictures website links to http://www.jurassicworld.com/ which then, for me at least, redirects to http://www.jurassicworldmovie.co.uk/ which is where the first size is taken from.


If the shark that the Mosasaur eats is about 3 meters long which is the average length of a Great White Shark, and if the Mosasaurs head is about 2x the size of the shark, the head is about 6 meters long. Since the head is about 1/4 of the total length of the creature, 1/4=6 Meters, 4/4=24 meters. The mosasaur is about 24 meters.

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