An international team of researchers has discovered that extroverted gorillas tend to live longer.
The 18-year study of 298 gorillas in North American zoos and sanctuaries examined the role of personality – traits that were measured against methods used to qualify humans and other primates.
"These findings highlight how understanding the natural history of personality is vital to insuring the continued health and well-being of humans, gorillas and other great apes," said Alex Weiss of the University of Edinburgh’s School of Philosophy, Psychology and Language Sciences and one of the study's authors.
"A large body of literature indicates that who we are or our ‘character’ has major consequences related to our health.'
Researchers zeroed in on four traits: dominance, neuroticism, extraversion and agreeableness. Teams of volunteers, keepers and other caretakers were recruited to gauge each gorilla’s temperament over 18 years.
Of the four characteristics, extroversion was linked with longer survival.
The study, published in the Proceedings of the Royal Society B: Biological Sciences, suggests that extroversion is associated with behaviours such as play, curiosity, activity and sociability.
Scientists also found the link between extroversion and survival was not affected by age or gender, how the gorillas were reared or how many times the gorilla had moved location.
The findings are in line with those on humans – sociable humans also tend to live longer.
In May, American researchers published their findings on 500 Ashkenazi Jews over the age of 95, and 700 of their offspring. Ashkenazi, or Eastern European Jews, were selected because they are genetically homogeneous so differences are easier to spot.
In that study, people with traits that included being optimistic, easygoing, sociable and outgoing had longer life spans. The study by the Albert Einstein College of Medicine and Yeshiva University, based in New York City, was published in the journal Aging.
Gorillas shared a common ancestor with humans about 10 million years ago and analysis of their DNA has showed they are 30 per cent closer to humans than chimpanzees.
During the study, which ran between 1993 and 2011, 119 gorillas died – aged between two and 55.
The study concludes less anxiety, more conscientiousness and openness to experience are related to reduced risk of death.