A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
Lack of water is the #1 trigger of daytime fatigue.
148
The average cat sleeps about 2/3 of the day.
203
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
A new baby usually deprives each of it's parents around 350-400 hours of sleep in the first year. That is one entire nights sleep per week, per parent.
194