How Much Do Animals Sleep?

Most animals have a daily pattern of rest and activity. Some animals are more active during the day (diurnal) and some are more active during the night (nocturnal). How much time do animals spend sleeping? Well, it depends on the animal:

Species	Average Total Sleep Time (% of 24 hr)	Average Total Sleep Time (Hours/day)
Bat	82.9%	19.9 hr
Opossum	80.8%	19.4 hr
Python	75%	18 hr
Hedgehog	72.6%	17.4 hr
Armadillo	70.8%	17.0 hr
Human (infant)	66.7%	16 hr
Tree shrew	65.8%	15.8 hr
Hamster	62.4%	15 hr
Squirrel	62%	14.9 hr
Western Toad	60.8%	14.6 hr
Chimpanzee	57%	13.7 hr
Gerbil	54.4%	13.1 hr
Rat	52.4%	12.6 hr
Cat	50.6%	12.1 hr
Mouse	50.3%	12.1 hr
Rhesus Monkey	49.2%	11.8 hr
Rabbit	47.5%	11.4 hr
Duck	45%	10.8 hr
Dog	44.3%	10.6 hr
Bottle-nosed dolphin	43.3%	10.4 hr
Human (adult)	33.3%	8 hr
Pig	32.6%	7.8 hr
Guppy (fish)	29.1%	7 hr
Seal	25%	6 hr.
Human (elderly)	22.9%	5.5 hr
Cow	16.4%	3.9 hr
Sheep	16%	3.8 hr
Donkey	13.0%	3.1 hr
Horse	12.0%	2.9 hr
Giraffe	8.3%	2.0 hr

References: This table was adapted from threesources:

Tobler, I., Napping and polyphasic sleep in mammals, In Sleepand Alertness: Chronobiological, Behavioral and Medical Aspects ofNapping, edited by D.F. Dinges and R.J. Broughton, Raven Press, NewYork, 1989, pp. 9-31.
Campbell, S.S. and Tobler, I., Animal sleep: a review of sleep duration across phylogeny. Neuroscience and Biobehavioral Rev., 8:269-300, 1984.
Kryger, M.H., Roth, T. and Dement, W.C., Principles and Practice ofSleep Medicine, W.B. Saunders Co., Philadelphia, 1994, pp. 1067.

"Science Update" has a short (3 min.) real audio program on how marinemammals sleep.

Did you know?

The brain of a dolphin appears tosleepone hemisphere at atime.

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