A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
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People who sleep late have more mental stamina and can outperform early risers.
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The average cat sleeps about 2/3 of the day.
203
Honeybees never sleep.
276
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
You burn more calories sleeping than you do watching television.
348
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
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