Comparative observations on sleep.
D000818:Animals; D001188:Artiodactyla; D001522:Behavior, Animal; D001717:Birds; D002417:Cattle; D004289:Dolphins; D005143:Eyelids / Q000502:physiology; D005399:Fishes; D007031:Hypothalamus / Q000502:physiology; D011323:Primates; D012104:Reptiles; D012119:Respiration; D012890:Sleep; D013997:Time Factors