June 30, 2011

Happier Orangutans Live Longer

According to a new study, happier orangutans are more likely to live longer.

Researchers used a low cost method to measure the happiness of captive orangutans.

The scientists found in a follow-up study seven years later that the happier primates were, the more likely they were to still be alive.

The team asked the people who worked closely with each captive orangutan to participate in the study.  The researchers asked the keepers and carers to complete a questionnaire about individual animals they knew well.

"The assessment was modeled on [established] methods of assessing human well-being," Dr Alex Weiss, who is from the University of Edinburgh and led the study, told BBC.

The questionnaire posed four key questions, including how much time the orangutan spent "happy, contented and enjoying itself."

The team was able to see how happiness influenced the orangutans' lives by working out a happiness score for each of the 200 animals observed.  The team revisited the study seven-years later and could see a clear connection between happiness and longevity.

Professor Richard Byrne, a primate expert from the University of St Andrews who was not involved in this study, said that "the findings were clear".

"[The team has] worked out that the difference between an orangutan being rated as very happy, compared to very unhappy, equated to 11 additional years of life-expectancy," Byrne told BBC.

But, he continued, "the authors rightly point out that the data don't tell us whether some subtle sign of health or illness makes an orangutan act more or less happy, or if its the reverse - that something intrinsic to the individual orangutan, which shows up externally as happiness or sadness to us, predisposes the individual to be more likely to stay healthy or get ill."

The researchers said they hope their results will be used to improve and extend the lives of endangered orangutans.

"[In captivity], we might be able to extend life by more closely monitoring the health of an animal that seems unhappy," Dr Weiss told BBC.

He also said he believes the work could be applied to orangutans in the wild.

"There are lots of sanctuaries that are temporary homes for animals that are rescued having been captured by traders and hunters," Weiss told BBC.

"These happiness or well-being measures could be used to work out if an animal is ready to be reintroduced into the wild.

"I'd love to see this questionnaire being used more broadly."

The research was published in the journal Biology Letters.  The team will also present their findings at the Society for Experimental Biology Annual Conference in Glasgow on Sunday July 3.


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