Biostasis or Cryptobiosis is the ability of an organism to tolerate environmental changes without having to actively adapt to them. Biostasis is found in organisms that live in habitats that likely encounter unfavorable living conditions, such as drought, freezing temperatures, change in pH levels, pressure, or temperature. Insects undergo a type of dormancy to survive these conditions, called diapause. Diapause may be obligatory for these insects to survive. The insect may also be able to undergo change prior to the arrival of the initiating event.