A new study has found evidence great apes are prone to mid-life crisis, much like humans. It found that their well-being was high in youth, fell to a low in midlife and rose again in old age.
The well-being of 155 chimps was examined in zoos in Japan, 181 zoos in the United States and Australia and 172 orangs in zoos in the United States, Canada, Australia and Singapore.
Keepers, volunteers, researchers and caretakers who knew the apes well, used a four-item questionnaire to assess the level of contentment in the animals.
Psychologist Alex Weiss of Scotland's University of Edinburgh said all three groups of apes experienced mid-life malaise: a U-shaped contentment curve with the nadir at ages 28, 27 and 35, respectively, comparable to human ages of 45 to 50.
"We were just stunned" when data on the apes showed a U-shaped curve of happiness, said ProfessorAndrew Oswald of the University of Warwick.
"Maybe nature doesn't want us to be contented in middle age, doesn't want us sitting around contentedly with our feet up in a tree," he said.
"Maybe discontent lights a fire under people, causing them to achieve more" for themselves and their family.
ProfessorOswald told Morning Report it means there may be nothing middle-aged men or women can do about a mid-life malaise.
The study was published in the Proceedings of the National Academy of Sciences of the USA on Monday.