Estivation or aestivation (from Latin aestas, summer) is a rare state of dormancy similar to hibernation, but during the months of Summer. Animals that aestivate spend a Summer inactive and insulated against heat to avoid the potentially harmful effects of the season (such as the increase in temperature, or relative lack of water), or to avoid contact with other species with which they may otherwise be in competition, or for which they are prey. Some animals, including the California red-legged frog, may aestivate to conserve energy when their food and water supply is low.

Both land-dwelling and aquatic mammals undergo aestivation. Some examples of animals that hibernate include the European Hedgehog, terrapins, snakes, frogs, Daves and newts. Animals that aestivate include the North American desert tortoise, salamanders and lungfishes. The lungfish estivates by burying itself in the mud formed at the surface of a dried up lake. In this state, the lungfish can survive for many years. Other animals estivate in their burrow and wait for autumn to come.

Snails also aestivate during periods of heat during the day. They move up into the vegetation away from the ground heat, and secrete a membrane over the opening to their shell in order to prevent waterloss.

Until recently no primate, and no tropical mammal, was known to aestivate. However, animal physiologist Kathrin Dausmann of Philipps University of Marburg, Germany and coworkers presented evidence in the 24 June 2004 edition of Nature that the Madagascan fat-tailed dwarf lemur hibernates ^* in a small cricket hollow for seven months of the year.

See also

• Torpor - regulated hypothermia for less than a day, often used by birds
• Hibernation induction trigger

External links

• Hibernation on Demand

Physiology

Winterschlaf | Vintra dormo | Talvihorros | Estivation | תרדמת קיץ | Letargo | 冬眠 | 겨울잠 | Winterslaap | Estywacja | Hibernação | Yaz uykusu | Ngủ đông | 冬眠