Close friendship can improve survival chances of rhesus macaques

Washington: A new research shows that close friendships improve the survival chances of rhesus macaques (old world monkeys). University of Exeter scientists studied the social lives of female macaques on Monkey Island in Cayo Santiago, off Puerto Rico. The results were published in the journal Proceedings of the Royal Society.

Data spanning seven years revealed that females with the strongest social connection to another macaque - measured by factors including time spent together and time grooming each other's fur - were 11 per cent less likely to die in a given year. "We can't say for certain why close social ties help macaques survive," said lead author Dr Sam Ellis, of Exeter's Centre for Research in Animal Behaviour.

"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 focused on four measures of social connection which involve, associating with many other macaques, having strong connections to favoured partners, connecting the broader group (being a link by associating with several sub-groups) and a high rate of cooperative activities such as grooming.

Having strong connections to favoured partners provided the biggest boost to survival chances while having many connections was also linked with better survival rates.

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

"But it seems to have '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."