Mosasaur size comparison

Common Name Mosasaurus
Group Reptiles
Species Mosasaurus suspirita
Time Late Cretaceous
Diet Carnivore
Temperament Aggressive
XP For Kill 15 XP
PC Release Date October 14, 2015 (v219.0)
Favorite Kibble Kibble (Quetzal Egg)
Tameable Yes
Rideable Yes
Saddle Mosasaurus Saddle (lvl 75)
Platform Saddle Mosasaurus Platform Saddle (lvl 85)

Until recently, I believed the Ultramegalodon to be the greatest of the ocean predators. Then I discovered Mosasaurus Suspirita in the deeps. Not quite as fast, but much larger and stronger, the Mosasaurus rules the deep waters off the island. Growing up to 50 feet long, Mosasaurus is larger than almost every other aquatic creature I've encountered thus far.

Contrary to common belief, Mosasaurus cannot breathe underwater. Rather, it can hold its breath an incredibly long period of time, similar to a whale. Mosasaurus is a deep-sea marine lizard, not a fish. It spends most of its time in the deeps, and only comes up to surface to breathe, or chase prey with an engulfing chomp.


Despite its power, Mosasaurus is not ideal for all deep-water activities. Its slower swim speed makes the risk of drowning much higher when using Tylosaurus to reach oil deposits or silica pearls.

Having one with you as an escort, on the other hand, is probably the best oceanic defense available!

— The Dossier

The Mosasaurus or Mosasaur is a large, carnivorous aquatic reptile found in the deepest depths of the oceans of the Ark. The Mosasaurus is roughly 50 ft in length in game, only rivaled by the Plesiosaur, and is in fact an air breather and needs to come up for air periodically, and is said to be a better guardian than use in underwater travel/adventure.

Wikipedia has a more detailed and comprehensive article on Mosasaurus





An enormous marine lizard, Mosasaurus is one of the largest creatures found in the waters surrounding the island. It has four flippers to propel its massive body through the seas. A small, finned ridge runs down the length of its back before developing into a paddle-like tail. The solitary and territorial Mosasaur is fairly slow-moving, but with its size, it can cover more ground than one might expect, making them adept ambush predators that strike from below to inflict crippling wounds.


The Mosasaurus is found deep in the ocean and can be quite far from the shore. It often resides towards the edge of the map boundary, and can be surprisingly elusive. It behaves similar to the Plesiosaur. Mosasaurus has a fairly average aggro radius, and will pursue the player a fair distance horizontally. However, it will not follow the player into shallow water, much like the Plesiosaur. It also is not necessarily found near cave entrances like a Plesiosaur.


Another large aquatic beast, said to be both tamable and ride-able. Good as a guardian from larger beasts such as the Megalodon but is not reliable for aquatic travel due to its slow speed & need for air.




  • The Dossier was revealed on June 13, 2015.
  • It regenerates stamina while moving as fast as when standing still.
  • Like other aquatic/amphibious animals it has no oxygen stat, despite it being mentioned as breathing air in the dossier.
  • Despite what the dossier says, a tamed Mosasaurus is anything but slow, and under no circumstances slower than Megalodons. In fact, Ichthyossauruses or Mantas with high movement speed stats are much faster, but by the level a player can afford to tame a Mosasaur with relative safety (60+), oxygen is probably not a concern. Not to mention that the first saddle only unlocks at level 75, same as the scuba gear set (which excluding the leggings is extremely cheap). This, combined with high combat capabilities, make the Mosas and fellow Plesios ideal for deep sea exploration. Instead, Ichthies and Mantas are best used to farm silica pearls and Deep Sea Loot Crates. Megalodons, however, have a faster turning speed and are found in abundance across the seas of ARK, making them the "water alternative" to Direwolves.
  • Ark's marine beast is much larger than any known mosasaurus. The actual description is correct, but the in-game creature is much larger than 50 feet long, around 200 feet.
  • Extrapolating from the above and assuming that the real-world and in-game Mosasaurus have a similar body shape and density, the latter must have a mass of around 896 metric tons.
  • The dossier mentions in the 'Wild' section that the Mosasaurus is larger than almost every other aquatic creature, thus stating the existence of a larger marine creature. This is likely the '4th boss' that was refered to in ARK Digest 18 or the Leedsichthys.
  • The Mosasaurus cannot be rendered unconscious with a Bow/Slingshot/Longneck because they do not work underwater, unless you lure it to a cave and KO it.
  • A disturbingly large creature is shown in the Ichthy dossier where it compares size to an Ichthy to a Megalodon. A much larger creature is behind the Megalodon, which could be a Mosasaurus or a hinted-at underwater boss.

Trivia not relevant for the game

  • The Mosasaurus is actually not a fish, but an aquatic reptile, which means that an actual Mosasaurus cannot breathe underwater, it can only hold its breath for an incredibly large amount of time.
  • In the Dossier it mentions Tylosaurus, another genus of mosasaur. It's possible this could mean that Tylosaurus will be added to the game as a smaller, faster alternative to the Mosasaurus. However, the way Tylosaurus is used in the sentence suggests that the author might simply be mistakenly using the names Mosasaurus and Tylosaurus interchangeably.


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