Subnautica 2 guide hub
Early Access 1.1 reviewedBehavior-first field guide

Fauna, predators, and leviathans

Subnautica 2
Creatures Guide

Read the warning display, choose a safe scanning window, and understand the relationships that make each ecosystem feel alive.

First actionObserve
Primary toolBioscanner
Leviathan ruleKeep an exit

Encounter language

Read the animal before you scan it

Threat is situational. A creature that is harmless at range can become dangerous when defending territory, supporting another predator, or reacting to your vehicle.
01Behavior class

Passive

Keeps feeding, schooling, or cruising without turning to face you.

Approach slowly and scan from the side so you do not scatter the group.
02Behavior class

Defensive

Flares fins, charges electricity, postures, or watches you before acting.

Treat the display as a boundary. Back off, then circle to a safer angle.
03Behavior class

Aggressive

Turns directly toward you, accelerates, circles, burrows, or begins a coordinated pass.

Break line of sight, use terrain or a flare, and scan only during recovery.
04Behavior class

Parasitic

Attaches to fauna, structures, or vehicles and changes the host encounter.

Identify the host relationship before intervening; carry the tool the encounter expects.
05Behavior class

Leviathan

Controls a large territory and can turn a routine route into an escape sequence.

Observe first, keep an exit bearing, and decide whether the scan is worth the risk.
Adaptive Measures 1.1 changed the rules.Most creatures now flee after a Survival Multitool hit and enter a brief dizzy state after a Sonic Resonator hit, though defensive retaliation can still occur. Use those tools to create distance, not as a reason to linger.

Representative encounters

Recognize the cue, then choose the response

This field selection covers the encounter patterns that teach the most useful habits. It is intentionally a guide—not a searchable creature database.
Moderate threat

Opening shallows · Defensive pair

Foureye

Warning cue
A bonded pair turns its attention toward you after prolonged observation.
Safe response
Scan briefly from range and retreat if the pair pivots to face you.
Moderate threat

Outer Coral Gardens · Territorial herbivore

Hammerhead

Warning cue
A warning display precedes a ramming attempt when you stay inside its space.
Safe response
Move laterally during the warning and scan from a flank after it passes.
Moderate threat

Dolerite Spires · Electrical defense

Surge Jelly

Warning cue
Its body brightens as an electrical field begins to charge.
Safe response
Start near maximum scanner range and leave the radius when charging begins.
High threat

Sand and cave floors · Ambush predator

Sandspear

Warning cue
A suspicious lure or disturbed patch of sand marks the buried animal.
Safe response
Trigger it from range, dodge the lunge, then scan during its recovery.
High threat

Cliffs and rock faces · Swarm predator

Bullethead

Warning cue
Several small armored fish gather and begin a launch pattern.
Safe response
Avoid the center of the swarm; use a distraction and isolate one scan target.
High threat

Coral Gardens and Graveyard · Apex predator

Marrowbreach

Warning cue
It watches detected prey before committing to a fast attack.
Safe response
Stay close to solid cover and leave as soon as its approach begins.
High threat

Infected Angel Combs · Primary parasite encounter

Bloom Parasite

Warning cue
Infected growth and an active parasite turn the area into a tool-gated encounter.
Safe response
Scan before clearing the site and keep the Sonic Resonator ready.
Moderate threat

Alien Turbine region · Vehicle parasite

Electric Geordie

Warning cue
It closes on the Tadpole and can attach to drain its Power Cell.
Safe response
Stop near cover, exit deliberately, and deal with it before continuing the route.

Ecology in motion

One creature can change another

Some of the most dangerous encounters begin as a relationship: a hunting partner nearby, a parasite inside a host, or a small animal using a larger organism for shelter.
01Cooperative hunters

Houndgar + Marrowbreach

The smaller hunter flushes and marks prey, creating the opening for the larger predator. Spotting one should make you search for the other.

02Parasite and host

Tongue Thief + Epicurean

The host encounter changes when the parasite occupies its mouth. Check the animal before choosing a close scanning angle.

03Shelter and cleaning

Clown Crab + anemone

The small crab uses the anemone as cover while contributing to its host. Look for the relationship, not just an isolated scan target.

04Protective grouping

Jetocaris families

Adults and juveniles respond as a family unit when danger rises from the seafloor, making their group behavior part of the discovery.

Scan the relationship, not only the species.Watch who follows, flees, feeds, or becomes more aggressive when another animal appears. That context often predicts the next attack more reliably than size alone.

Bioscan protocol

Complete difficult scans without gambling the expedition

Creature scans fill the databank and now contribute to additional passive Biomod slots. A safe scan is a short operation with preparation, timing, and a planned exit.
01

Observe

Watch one full behavior cycle before closing distance.

02

Prepare

Top up oxygen, preserve an escape lane, and ready a distraction or Resonator.

03

Approach

Come from the flank, use terrain, and avoid swimming directly at the face.

04

Commit

Scan during feeding, recovery, or distraction—never after the attack has started.

05

Leave

Break contact immediately after completion instead of waiting for another opening.

Scan kit

Bring enough margin to abort

Bioscanner · spare battery · Air Bladder · healing · distraction flare · visible return bearing
How Biomods work

Leviathan protocol

Survival comes before scan completion

Leviathan-class fauna do not share a single behavior. Separate peaceful giants, environmental traps, mobile hunters, and boundary predators before choosing an approach.
01Leviathan-class grazer

Coral Crab

Give it room

Usually the safest giant to observe. Approach calmly, avoid crowding it as it emerges, and leave a wide path around its body.

02Stationary trap

Great Jaw

Extreme

Treat the shell as terrain with a lethal center. Stay above or behind it and do not cross through the tendon-filled opening.

03Mobile hunter

Collector Leviathan

Extreme

Use terrain and distractions. In co-op, one diver can hold its attention while the scanner approaches from a different direction.

04Boundary predator

Shiver Leviathan

Turn around

The red boundary is the warning. Do not turn a routine expedition into a completionist scan unless the team has accepted the loss risk.

Abort rule: if the creature blocks the return route, the distraction fails, or a teammate loses visual contact, abandon the scan and regroup. Databank progress is never worth losing the expedition.

Encounter understood

Connect fauna to the world around it

Use the Biomes guide to learn where encounter patterns change, or continue to Biomods to understand how Bioscans support adaptation progression.
Creature systems reviewed against the official Adaptive Measures 1.1 update