BFFs: Close friends help macaques survive

When it comes to macaques, they get by with a little help from their friends.

Close friendships improve the survival chances of the monkeys, new research suggests.

And having a BFF – close friend – provided the greatest boost to life chances.

Scientists studied the social lives of female rhesus macaques on “Monkey Island” – Cayo Santiago, off Puerto Rico.

They found that those with the strongest social connection to another macaque – measured by factors including time spent together and time grooming each other’s fur – were 11% less likely to die in a given year.

The results were based on data spanning seven years.

Lead author Dr Sam Ellis, from the University of Exeter’s centre for research in animal behaviour, said: “We can’t say for certain why close social ties help macaques survive.

“Having favoured partners could be beneficial in multiple ways, including more effective cooperation and ‘exchange’ activities such as grooming and forming coalitions.

“Many species – including humans – use social interactions to cope with challenges in their environment, and a growing number of studies show that well-connected individuals are healthier and safer than those who are isolated.”

The study looked at four measures of social connection – associating with other macaques, having strong connections and favoured partners, connecting the broader group, and a high rate of cooperative activities such as grooming.

Researchers say having strong connections to favoured partners, provided the greatest boost to survival chances, while having many connections was also linked with better survival rates

Connecting a broader group and engaging in high rates of grooming were found to bring no survival benefits.

The macaques on Monkey Island have been studied for decades, and the researchers combined existing data with a study of social connections.

Dr Lauren Brent, also of the University of Exeter and the senior author of the study, said: “Having many social connections might mean a macaque is widely tolerated – not chased away from food, for example.

“But it seems having ‘close friends’ brings more important benefits than simply being tolerated.

“These favoured partners have the opportunity to provide each other with mutual support and cooperation, making both parties more likely to survive.”

The study, supported by National Institutes of Health (NIH), is published in the journal Proceedings of the Royal Society B.