which group experiences the highest level of rem sleep
Rapid eye movement sleep Although it manifests differently in different animals, REM sleep or something like it occurs in all land mammals as well as in birds. The primary criteria used to identify REM are the change in electrical activity, measured by EEG, and loss of muscle tone, interspersed with bouts of twitching in phasic REM.[85] The amount of REM sleep and cycling varies among animals; predators enjoy more REM sleep than prey.[17] Larger animals also tend to stay in REM for longer, possibly because higher thermal inertia of their brains and bodies allows them to tolerate longer suspension of thermoregulation.[86] The period (full cycle of REM and non-REM) lasts for about 90 minutes in humans, 22 minutes in cats, and 12 minutes in rats.[87] In utero, mammals spend more than half (50â€“80%) of a 24-hour day in REM sleep.[22]