We know from human studies that the best predictor of longevity in humans is not wealth or social status but the presence of a strong and supportive social network. The research on baboons suggests that this finding is not unique to humans.
Professor Robert Seyfarth
A recent paper published in Proceedings of the National Academy of Sciences
) has allowed researchers to link social skill, personality traits and reproductive success for the first time in wild primates. Professor Robert Seyfarth and Professor Dorothy Cheney from the University of Pennsylvania
, with the assistance of students and colleagues, have spent the last 17 years observing baboon behaviour in the Moremi Game Reserve
in Botswana, and the latest study constitutes a fragment of the detailed information they have gleaned on baboon society.
Although baboon societies are strongly hierarchical and matrilineal, the team were surprised to find that social status could not explain the reproductive success and long lifespan of lower-ranking individuals. They spent seven years observing and quantifying the sociability of female baboons in the group, and found that some were more markedly better at maintaining personal relationships than others.
Working alongside Professor Joan Silk of Arizona State University, Professor Seyfarth and Professor Cheney identified three broad personality types among the female baboons – ‘nice’, ‘aloof’ and ‘loner’. ‘Nice’ females formed strong and lasting bonds and were friendly to all other females. ‘Aloof’ baboons were more aggressive and formed weaker bonds, while ‘loner’ individuals were often and bonded weakly with changing partners.
Professor Seyfarth explained to ScienceOmega.com
how these differing personality types impacted on the health and reproductive success of the baboons and what this might infer about primate societies more generally…
What prompted you and your colleagues to examine this aspect of baboon society?
When our earlier papers showed that, among female baboons, longevity and offspring survival were best predicted by the strength of a female's social relations with other females, we naturally wanted to look more closely to see if we could determine what individual characteristics – or personality styles – were best associated with strong social bonds.
What observations did you make about the bonds between female baboons?
Our earlier work has shown that the strength and stability of social bonds in female baboons varies widely. Bonds are typically measured by the amount of grooming between two individuals, and also by how often they approach one another and respond to each other's requests for grooming. Females who formed strong, enduring bonds with other females, and whose close female partners remained stable from year to year, had the highest rates of offspring survival and the greatest longevity.
How does this impact upon the success and health of the individual?
Forming strong social bonds seems to improve an individual's health. Individuals with a tightly focused grooming network have lower stress levels and are, reproductively speaking, more successful.
Were you surprised to find the effect couldn’t be explained by social rank and/or family size?
We were somewhat surprised, because rank is a very noticeable part of baboon society and because females tend to form their closest bonds with their close female kin – their mothers and daughters and sisters. On the other hand, some females have no close relatives in the group and they often manage to do very well, while some individuals in large families nonetheless do not have any close social bonds. So we knew that there must be some explanation for this variation that did not depend on rank or the availability of kin.
What are the implications of the findings?
We know from human studies that the best predictor of longevity in humans is not wealth or social status but the presence of a strong and supportive social network. The research on baboons suggests that this finding is not unique to humans. The importance of strong social relationships does not depend on culture or language, and it is not restricted to species with language and advanced cognitive abilities. Instead, it appears in animals whose societies are not as complex as ours.
Do you plan to investigate the topic in greater detail?
We continue to work on the evolution of cooperation and adaptive personality characteristics in baboons and other nonhuman primates.