Kryobios är en extrem form av frystolerans kännetecknad av bevarad livsduglighet, följt av ett metaboliskt avbrott inducerat av en låg temperatur.

Cryptobiosis is an ametabolic state of life entered by an organism in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all measurable metabolic processes stop, preventing reproduction, development, and repair. When environmental conditions return to being hospitable, the organism will return to its metabolic state of life as it was prior to the cryptobiosis.

Cryobiosis is a form of cryptobiosis that takes place in reaction to decreased temperature. Cryobiosis initiates when the water surrounding the organism’s cells has been frozen, stopping molecule mobility and allowing the organism to endure the freezing temperatures until more hospitable conditions return. Organisms capable of enduring these conditions typically feature molecules that facilitate freezing of water in preferential locations while also prohibiting the growth of large ice crystals that could otherwise damage cells.