There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Dieters who sleep more take off more fat that those who sleep less.
159
Honeybees never sleep.
276
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
Bats sleep 18-20 hours per day.
5
The human brain is more active during sleep than during the day.
28