The average cat sleeps about 2/3 of the day.
203
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
Cows can sleep standing up, but they can only dream lying down.
745
Termites work 24 hours per day and they do not sleep.
57
47% of people have a nightmare at least once a month.
186
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