Estivation
Estivation or
aestivation (from
Latin aestas, summer) is a rare state of
dormancy similar to
hibernation, but during the months of the
summer. Animals that estivate 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 estivate to conserve energy when their food and water supply is low.
 |
The lungfish, a species which undergoes estivation. |
Both land-dwelling and aquatic mammals undergo estivation. Animals that estivate include
North American desert tortoises,
salamanders and
lungfishes. The lungfish estivates by burying itself in 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 estivate during periods of heat during the day. They move into the vegetation, away from the ground heat, and secrete a membrane over the opening to their shell in order to prevent water loss.
Until recently no
primate, and no
tropical mammal, was known to estivate. 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 or estivates in a small cricket hollow for seven months of the year.
*
Torpor - regulated hypothermia for less than a day, often used by birds
*
Hibernation induction trigger*
Hibernation on Demand
