A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Lack of water is the #1 trigger of daytime fatigue.
148
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
The strangers in your dreams are actually people that you've seen in real life.
50
47% of people have a nightmare at least once a month.
186
People who sleep late have more mental stamina and can outperform early risers.
33
You forget 90% of your dreams.
256