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Sleep can follow a physiological or behavioral definition. In the physiological sense, sleep is a state characterized by reversible unconsciousness, special brainwave patterns, sporadic eye movement, loss of muscle tone (possibly with some exceptions; see below regarding the sleep of birds and of aquatic mammals), and a compensatory increase following deprivation of the state, this last known ...
Some crepuscular animals may also be active by moonlight or during an overcast day. Matutinal animals are active only after dawn, and vespertine only before dusk. A number of factors affect the time of day an animal is active. Predators hunt when their prey is available, and prey try to avoid the times when their principal predators are at large.
Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours, with 13 to 14 being the average. Some cats can sleep as much as 20 hours. The term "cat nap" for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period.
Social hierarchy, diet, brain size and body mass are contributing factors to how much sleep particular animals naturally need. Outside factors might even i Research Shows that Animals, too, Need a ...
Within a few months of postnatal development, there is a marked reduction in percentage of hours spent in REM sleep. By the time the child becomes an adult, he spends about 6–7 hours in NREM sleep and only about an hour in REM sleep. [46] [47] This is true not only of humans, but of many animals dependent on their parents for food. [48]
The activity/rest cycle (sleep) in animals is one of the circadian rhythms that normally are entrained by environmental cues. In mammals, such endogenous rhythms are generated by the suprachiasmatic nucleus (SCN) of the anterior hypothalamus. Entrainment is accomplished by altering the concentration of clock components through altered gene ...
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Free-running sleep is a rare sleep pattern whereby the sleep schedule of a person shifts later every day. [1] It occurs as the sleep disorder non-24-hour sleep–wake disorder or artificially as part of experiments used in the study of circadian and other rhythms in biology .