Additional Creatures Wiki

Hydrotherosaurus are reptiles in Additional Creatures.


An Elasmosaur, Hydrotherosaurus is a peaceful reptile of the ocean, sometimes found swimming in small groups. With a long, craning neck, Hydrotherosaurus uses it to deliver precise strikes into fish schools, snapping up an easy meal. While less aggressive, powerful, and durable than ark's plesiosaur, the Hydrotherosaurus has its own uses when tamed. It is intelligent enough to notice a survivor riding on a creature's back and will target the rider before the creature- using its craning neck to attack the rider directly. Tamed, this makes Hydrotherosaurus a great combat mount. it can use its long neck to reach a far distance and attack enemy riders directly- removing them and making the critter much more easy to deal with. Aside from that though, Hydrotherosaurus is a poor fighter. Its durability and power are low compared to other ocean heavyweights, and it's long neck is pitiful in combat. Once a target comes into close quarters combat, Hydrotherosaurus becomes inable to hit successfully, making combat with Hydrotherosaurus all about keeping one's distance. On the more passive side, they have great stamina- making them excellent for the oceanic long-haul.

Color Regions

Male -

Color Region 1 - Neck Rings

346110 screenshots 20200316190509 1.jpg

Color Region 2 - Underside

346110 screenshots 20200316190537 1.jpg

Color Region 3 - Head Patches, Shading

346110 screenshots 20200316190553 1.jpg

Color Region 4 - Shading

346110 screenshots 20200316190608 1.jpg

Color Region 5 - Pattern

346110 screenshots 20200316190628 1.jpg

Female -

Color Region 1 - Pattern Outline

346110 screenshots 20200316191844 1.jpg

Color Region 2 - Underside

346110 screenshots 20200316191909 1.jpg

Color Region 3 - Main Body

346110 screenshots 20200316191924 1.jpg

Color Region 4 - Pattern Outline

346110 screenshots 20200316191949 1.jpg

Color Region 5 - Pattern Shading

346110 screenshots 20200316192004 1.jpg

Base Stats, Controls, and Abilities

Attribute Base Stat
Health 1950
Stamina 600
Food 9200
Weight 800
Melee Damage 185%
Movement Speed 100%
Torpidity 2200

Left Click - Directional Bite

28 Base Damage - Directly Damages Riders - Instantly Kills Small Fish - Gathers Organic Polymer

Right Click - Forward Bite

28 Base Damage - Directly Damages Riders - Instantly Kills Small Fish - Gathers Organic Polymer

C - Roar

Hydrotherosaurus is immune to electrocution.


  • Hydrotherosaurus means "Water Beast Lizard".
  • Hydrotherosaurus lived in the waters of what is now California during the Late Cretaceous period, 66 million years ago. It's one of the most notable marine species known from that region during that time.
  • Hydrotherosaurus had the longest neck to body ratio of any known plesiosaur.
  • Hydrotherosaurus was originally going to be called "Elasmosaurus", but this was decided against as that taxon is represented in ARK with the "plesiosaurs".
  • Hydrotherosaurus has sexual dimorphism in its patterns. While both have banded necks, the bands on the male are much more notable and distinct, while the female has a unique set of stripes running along the dorsal of her body as well as a lateral stripe on the neck.