A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
You burn more calories sleeping than you do watching television.
348
Cows can sleep standing up, but they can only dream lying down.
745
There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12
Bats sleep 18-20 hours per day.
5
You forget 90% of your dreams.
256