Cows can sleep standing up, but they can only dream lying down.
745
You can reschedule your sleeping pattern by not eating 12-16 hours before you want to be awake. Upon eating after this time period, your internal clock will reset to a new day, with the time of your first meal being interpreted as "morning".
11
Bats sleep 18-20 hours per day.
5
The human brain is more active during sleep than during the day.
28
The strangers in your dreams are actually people that you've seen in real life.
50
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23