WHY DO SOME ANIMAL SLEEP SO MUCH?

© Provided by Live Science Some pets are champion sleepers. A dog snoring away the afternoon on the living room floor. Walruses snoozing belly-up on a beach. Lions sprawled out on the Serengeti. A hippo dozing on a mudbank. These slumberous scenes may make folks wonder why these other mammals seem to be getting so much more sleep than humans. Do they actually need more sleep? Ar...