Sunset in Subnautica

Chronobiology is a field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar and lunar related rhythms. The processes primarily seen in subnautica are a form of what is known as circadian rhythm, which is any biological process that displays an endogenous and entrainable oscillation of about 24 hours (this oscillation time is different due to the nature of the day cycle in subnautica).

Some life forms in Subnautica respond to light. This is unrelated to Chronobiology, as the concept of response to light works similar to the concept of fear. It does not correlate with the in-game time, although it might appear like it (e.g. a less prominent fleeing behavior due to a sleep cycle).

Cycles Observed in Subnautica


Cathemerality is a plant or animal behavior characterized by activity during the day and night.

  • All life forms not listed in other categories are Cathemeral.



Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day.