Happy Orangutans Live Longer

Courtesy of Aaron Logan

Happier orangutans live longer, Scottish researchers say, a finding that could shed light on the evolution of happiness in humans. Researchers at the University of Edinburgh, working with colleagues at the University of Arizona, used an innovative approach to assessing happiness by asking zoo and animal park keepers who work with orangutans to answer questions on the animals’ behalf.

The keepers of 184 orangutans were asked how often the animal was in a good mood as opposed to a bad mood, how much it enjoyed social interactions and whether it was effective at achieving its goals. Orangutans in the study which were scored as happier by their keepers were significantly more likely to be alive up to seven years later, researchers said, and the effect remained even when factors such as sex, age and species were taken into account.

These results could shed light on how happiness evolved in all primates including humans, a leader of the study said. “Already we have shown that certain personality traits linked to happiness share the same genetic basis in humans and chimpanzees,” Edinburgh’s Alexander Weiss said.

“Studying these relationships across a wide range of species could yield fascinating insights into the evolutionary bases of happiness, depression and a host of other psychological characteristics that impact the lives of humans and, most likely, a range of other species.” Although happiness has been linked to longer life in humans and now orangutans, the basis for this is not well understood, Weiss said. “It is unlikely that happiness [alone] causes longer life; the association is almost certainly more complex,” he said.

The findings have been published in Royal Society journal Biology Letters.