Definition Sleep in non-human animals

sleep can follow physiological or behavioral definition. in physiological sense, sleep state characterized reversible unconsciousness, special brainwave patterns, sporadic eye movement, loss of muscle tone (possibly exceptions; see below regarding sleep of birds , of aquatic mammals), , compensatory increase following deprivation of state. in behavioral sense, sleep characterized minimal movement, non-responsiveness external stimuli (i.e. increased sensory threshold), adoption of typical posture, , occupation of sheltered site, of repeated on 24-hour basis. physiological definition applies birds , mammals, in other animals (whose brain not complex), behavioral definition more used. in simple animals, behavioral definitions of sleep ones possible, , behavioral repertoire of animal may not extensive enough allow distinction between sleep , wakefulness.

sleep reversible, opposed hibernation or coma, , sleep deprivation followed longer or deeper rebound sleep.