When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
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Some lizards, in which the tail is a major storage organ for accumulating reserves, will return to a dropped tail after the threat has passed, and will eat it to recover part of the sacrificed supplies.
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A dairy cow can produce more milk when listening to music.
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Crows living in some urban areas drop nuts into traffic to let the passing cars crush them, then they wait for the red lights to stop the traffic so they can grab and eat it.
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Parrotfish make themselves a kind of mucus 'sleeping bag' which masks their smell from predators and keeps parasites away.
4
When Koko, the gorilla famous for knowing sign language, was asked where gorillas go after death, she responded by signing “Comfortable hole, bye.”
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A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
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