for National Geographic News
Female baboons that enjoy the close company of others raise more successful offspring than do baboons who lead a more solitary life, according to results from an ongoing, long-term research project in Kenya.
"Social animals actually seem to spend a lot of time forming social bonds. They invest so much [effort] it's hard to imagine that [social bonds] don't matter. But no one had ever shown that they did," said Susan Alberts, a biologist at Duke University in Durham, North Carolina, and researcher behind the study.
The finding by Alberts, along with colleagues Joan Silk, an anthropologist at the University of California, Los Angeles, and Jeanne Altmann, a behavioral ecologist at Princeton University in New Jersey, is described in tomorrow's issue of the journal Science.
According to their study, the more social a female baboon is, the more likely her baby is to survive the hardships of infancy and reach the one-year-old mark, the age comparable to that of a five-year-old human. The benchmark signals that a juvenile baboon has a good chance of surviving into adulthood and breeding.
"In evolutionary terms, sociality is good for you," wrote Robin Dunbar, a behavioral ecologist at the University of Liverpool in England, in an accompanying commentary.
The researchers' finding is based on 16 years worth of data collected from observations of wild savannah baboons (Papio cynocephalus) in Kenya's Amboseli Basin, a wooded grassland in the shadow of Mount Kilimanjaro.
"To test this hypothesis, we had to begin several decades ago and design a data scheme that would gradually yield the nuggets that led to this finding. No quickie shortcuts here," said Altmann, who co-directs the Amboseli Baboon Research Project with Alberts.
Observations in the Amboseli have revealed the complexities of baboon social life. Both sexes have several different mates throughout their lives. Females stay in the same baboon group forever, while males may roam from group to group.
When not foraging for food or sleeping, baboons spend social time hanging out together and picking twigs from each other's fur.
"The primary interactions are groomingthe equivalent of giving or receiving a good massage[and] being in contact," said Altmann.
Female baboons tend to form the tightest bonds with their mothers, aunts, and sisters. The bonds between maternal or paternal sisters are particularly close. Since a male may live in several groups over the course of his life, his bonds are not always as strong. But they, too, are important, according to the researchers.
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