Happy humans tend to live longer, and the same appears to hold true for orangutans. In a new study, published online today in Biology Letters, researchers surveyed the well-being of 184 zoo-housed orangutans by asking zookeepers to answer a four-item questionnaire. Keepers were asked to rate the orangutans' general positive mood, social life, and ability to reach desired locations and objects. Those orangutans judged to be the happiest were 42% less likely to pass away within 7 years after the survey was taken. The researchers suspect that, just like humans, happier apes tend to have less stress and health problems, which helps them to live longer.
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