A recent study found that men sleep just fine with someone next to them but women don't. So next time you're staring at the ceiling in the dark while your partner snores, think about this: A brown bat needs 20 hours of rest a day; a giraffe, just two hours. But an adult human needs eight hours, and a lack of blissful slumber is associated with everything from poor cognitive function to 100,000 auto accidents and 1,500 deaths a year. Don't let that keep you up.

- Time