Cryptobiosis is a state of suspension of biological activity in which the intensity of internal processes drops to a fraction which may be very low, from its usual level. It is a form of resistance which makes the cryptobiotic animal very resistant to cold, heat and weather in particular.
It can be considered an extreme of hibernation. Nematodes in an encysted state can stay for more than ten years in a dry environment before returning to their worm form, taking advantage of the favorable living conditions that their host provides. Rotifers and some insects and crustaceans are also capable of entering cryptobiosis when the living conditions of their environment become difficult.