When cats are happy, they may squeeze their eyes shut.
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Sandy, an African Penguin, has been in 'love' with her keeper at the Nuremburg zoo since 1996.
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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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Ten seconds of hugging a day increases levels of oxytocin, which can reduce blood pressure, thus cutting the risk of heart disease.
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