How do female baboons live long and prosper? A big social network helps, according to a new report by scientists from University of Notre Dame, in Indiana, and the Institute of Primate Research in Kenya.
Researchers have been observing a population of wild baboons in Amboseli National Park, in Kenya, for 30 years. "We can tell individual baboons apart by distinct features of their appearance, such as their fur color, the shape of their tail, or how they move," says Elizabeth Archie, a University of Notre Dame ecologist and an author of the study, in a statement.
Archie and her colleagues analyzed the social habits of roughly 200 female monkeys, seeing how often they groomed or were groomed by other males and females. "We especially focused on grooming interactions, which are a sign of social support in baboons," Archie says. "Baboons spend more time grooming their 'friends', and baboons with stronger grooming connections seem to live longer." In fact, the top quarter of females on the "social connectedness" scale lived longest, the researchers say. Being friendly with adult males was associated with a decrease in risk of death by 45 percent, and adult female friends lowered the likelihood of dying by at least 34 percent.
It's not just baboons who get a boost from friendship - humans do, too, the researchers say. "I think the results are applicable to humans," Archie says. "Specifically, there have been a handful of studies that have shown that an animal's social connections can predict their longevity, including research on rats, dolphins and baboons."
Though the science is sparse compared with the research on families and marriage, a few studies have tied deep friendships to healthy people. "Friendship has a bigger impact on our psychological well-being than family relationships," sociologist Rebecca Adams told the New York Times in 2009.
"Across a range of circumstances, people who receive more social support tend to live longer than people who are socially isolated," Archie says. "Our results suggest that this phenomenon might be part of our shared biological history with other mammals."