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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A couple had their wedding rings engraved with a waveform of their own voices saying "I do."
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A zoo in China gave a gay penguin couple the opportunity to raise a chick.
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In 2011, archaeologists discovered the skeletal remains of a Roman couple who have been holding hands for 1,500 years.
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Dolphins have names for one another.
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Kissing releases masses of oxytocin, a "love potion" that helps couples bond and feel more attracted to each other.
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