Sleep and Estivation (Shallow Torpor): Continuous Processes of Energy Conservation

Abstract

Estivation (shallow torpor) in the round-tailed ground squirrel (Citellus tereticaudus) is entered through electrophysiologically defined states of sleep. Rapid-eye-movement sleep diminishes as body temperature falls in such a way that, at a body temperature of 26 degrees to 28 degrees C, torpor is characterized by almost continuous slow-wave sleep isomorphic with that observed at euthermic body temperatures.