Sea otters hold hands while sleeping so they don’t drift away from each other.
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In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
47% of people have a nightmare at least once a month.
186
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
People who sleep late have more mental stamina and can outperform early risers.
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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 record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15