Researchers have found that female baboons with well-connected same-sex friends live longer and are more likely to raise their offspring to maturity. The study, just published in the journal Royal Society Open Science, showed that close friendships affected a female’s reproductive success more than overall social status.
Scientists from the University of Pennsylvania and Arizona State University collaborated in a 15 year study. They studied a group of wild chacma baboons in Botswana and based their results on 7 of those years, during which the group was continuously monitored. The group of baboons had been first observed in 1978 and the relatedness of individuals was already known. They focused their attention on 49 adult females and analyzed their interactions with each other and the group. The researchers also measured factors such as reproductive success, lifespan, stress levels, and dominance rankings.
The researchers found that having well-connected female friends was the greatest predictor of offspring survival. In addition, females that maintained close friendships with other females in healthy relationships had longer lifespans. These friendships were more important than overall social status. Having a close friend who has connections increased the chance of offspring survival more than having a higher dominance rank. Females that stayed in small “cliques”, ignoring most of the group, didn’t gain the same benefits as females with well-connected friends.
There are a couple of possible explanations for the importance of these same-sex friendships. By maintaining connections with multiple group members, group interactions may be less stressful in general. The authors also believe that these connections help if a female loses her partner or best friend. If her closest friend dies, having “friends of friends” will help her develop new partnerships quickly.
The study outlines the importance of social networks in species that regularly interact in group settings. The team plans to continue their research on baboon social interactions and hopes to further investigate the importance of same-sex friendships.
Dorothy L. Cheney et al. Network connections, dyadic bonds and fitness in wild female baboons. Royal Society Open Science (2016).