Estivation << `ehs` tuh VAY shuhn >> is an inactive state that occurs in the life of some animals during hot, dry periods. The word is also spelled aestivation. Animals that estivate are protected from dryness in much the same way as those that hibernate are protected from cold. When an animal estivates, its breathing, heartbeat, and other body processes slow down. This reduction in activity decreases the need for water. The animal can thus survive hot, dry periods in which it otherwise might die.
Many amphibians and reptiles estivate, as do some insects, snails, and fish. Fish that estivate live in ponds and streams that evaporate during the dry season. Some estivators, including various kinds of frogs, lungfish, and salamanders, form a cocoon just before entering estivation. The cocoon helps prevent water loss from the skin. The animal awakens from estivation after the dry season and emerges from its cocoon.
See also Hibernation; Lungfish.
