Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15
Cows can sleep standing up, but they can only dream lying down.
745
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
44% of kids watch television before they go to sleep.
106
There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12