Do you think your pet sleeps a lot? Well here are some fun facts. Dogs sleep an average 12-14 hours per day, while cats sleep an average of 12.5 hours a day. Horses and elephants only sleep 3-4 hours a day, whereas the little brown bat sleeps up to 20 hours a day! Some species have special adaptations for sleep. Dolphins and whales avoid drowning by sleeping with only half of their brain at a time, and some migrating birds can sleep while flying!