December 14
Giraffes need less sleep than any other mammal. They normally nod off--often standing up--for just a few minutes at any one time, for a total of only 20 to 30 minutes in a day.
As a rule of thumb, the larger the animal, the less it sleeps. For example, elephants sleep just 3 to 4 hours a day, your pet cat around 12. Armadillos and opossums linger in the sack for 18 or more hours daily, while bats dream their upside-down dreams up to 20 hours a day.
Researchers studying marine mammals and certain birds have determined that these creatures can sleep with only one hemisphere of the brain at a time, the other remaining awake. Whales and dolphins sleep this way almost exclusively, to ensure that they surface to breathe. Seals and sea lions can sleep with both halves of the brain simultaneously if they haul out on land.
posted by Peggy or Guy at 11:06 PM 