How do animals sleep?

HOW DO ANIMALS SLEEP? GIRAFFE HOURS OF SLEEP PER DAY Sleeps standing up, occasionally curled up. Light sleep mixed with series of short deep naps. 01 02 03 BOTTLENOSE DOLPHIN 04 Remains swimming while half of its brain rests. Usually sleep at night for 05 a few hours at a time. 06 07 HUMAN 08 Sleeps at night. Horizontal. 09 10 11 KINKAJOU Sleeps high in trees during the day. Snuggles with its long tail. 12 13 14 CAT 15 Day or night. Sleeps in a ball, plus assorted silly positions. 16 17 18 KOALA 19 Sleeps during the day and naps at night. 20 21 22 BULLFROG 23 Scientists suspect that bullfrogs do not sleep. World Science Festival More studies are needed. 24