A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
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Sea otters hold hands while sleeping so they don’t drift away from each other.
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People who sleep late have more mental stamina and can outperform early risers.
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In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
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A new parent will lose about 1055.6 hours of sleep in the first year of their child's life - almost 44 days!
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Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
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