Chimpanzees and orangutans too, can experience a mid-life crisis just like humans, a study suggests.
This is the finding from a new study that set out to test the theory that the pattern of human well-being over a lifespan might have evolved in the common ancestors of humans and great apes.
A team of researchers - including professor of economics Andrew Oswald, and psychologist Alex Weiss from the Universities of Warwick and Edinburgh, respectively - discovered that, as in humans, chimpanzees and orangutan well-being follows a U-shape and is high in youth, falls in middle-age, and rises again into old-age.
The authors studied 508 great apes housed in zoos and sanctuaries in the US, Japan, Canada, Australia and Singapore, the journal Proceedings of the National Academy of Sciences reported.
The apes' well-being was assessed by keepers, volunteers, researchers and care-takers who knew the apes well. Their happiness was scored with a series of measures adapted from human subjective well-being measures, according to a Warwick and Edinburgh statement.
Oswald said: "We hoped to understand a famous scientific puzzle: why does human happiness follow an approximate U-shape through life?"
"We ended up showing that it cannot be because of mortgages, marital break-up, mobile phones, or any of the other paraphernalia of modern life. Apes also have a pronounced mid-life low, and they have none of those," concluded Oswald.
The team included primatologists and psychologists from Japan and the US.