ScienceDaily (Oct. 1, 2012) Whether human or baboon, it helps to have friends. For both species, studies have shown that robust social networks lead to better health and longer lives. Now, a team of University of Pennsylvania researchers has helped show that baboon personality plays a role in these outcomes, and, like people, some baboons' personalities are better suited to making and keeping friends than others.

The research was conducted by psychology professor Robert Seyfarth and biology professor Dorothy Cheney, both of Penn's School of Arts and Sciences. They collaborated with the Arizona State University's Joan Silk.

Their work was published in the Proceedings of the National Academy of Sciences.

Seyfarth and Cheney, along with their colleagues and students, have spent the last 17 years observing a group of baboons living in the Moremi Game Reserve in Botswana, studying the biological roots of their social dynamics. As with many other primates, baboon societies are strongly hierarchical. Females "inherit" their dominance ranks from their mothers and enjoy priority of access to food and mates. But high-ranking females do not always have greater reproductive success than low-ranking females. This suggests that, when it comes to evolutionary success, the inherited advantage of high rank can't explain everything.

"If you look at a baboon society," Seyfarth said, "and see the ranked, matrilineal families, you would think that whatever traits put an individual at the top of the hierarchy, that's what natural selection is going to favor. But that turns out not to be the case.

"In fact, dominance rank is not as good a predictor of reproductive outcomes as a close network of social relationships and stable relationships over time. So our question became 'What predicts having a strong network?'"

Baboon females actively work to maintain close social bonds, but, like humans, some baboons seemed to be better at it than others. With such traits closely tied to fitness and reproductive success, the Penn researchers wanted to get at the root of this variation.

During seven years of observations in the animals' natural habitat, the researchers measured individual female baboons on their sociability. They measured the number of grooming partners a baboon had, as well her tendency to be friendly or aggressive toward others. They also measured reproductive and fitness benefits they accrued: how long individuals and their offspring lived, as well as their stress levels, as determined by the presence of certain hormones in their droppings.

The researchers found that strength of an individual's social bonds was not fully predicted by seemingly obvious factors, such as the female's rank or the size of the family she was born into.

"Even when a female has a lot of relatives," Cheney said, "sometimes she's a loner, but some females who have no relatives do just fine. It suggests that you have to be both lucky and skilled to have these networks."

Read the original post:
Baboon personalities connected to social success and health benefits