Grieving Baboons Comforted by Friends
By Jennifer Viegas, Discovery News
Feb. 10, 2006 - Female baboons that suffer the loss of a close friend or relative turn to other baboons for comfort and support, according to a new study that encompassed 14 years of observing over 80 free-ranging baboons in Botswana's Okavango Delta.
The study provides the first direct evidence that certain animals mourn the loss of individuals, even when the rest of their social group remains intact. The findings also suggest that friendship may be just as important to some primates as it is for humans.
Researchers particularly were struck by the behavior of one female chacma baboon (Papio hamadryas ursinus) named Sylvia, who was described as "the queen of mean" and disdainful of other baboons until she lost her daughter, Sierra, to a lion kill.
"In the week after Sierra died, Sylvia was withdrawn," said Anne Engh, who led the project. "When the other females were grooming and socializing, she tended to sit alone and rarely interacted even with her other relatives."
Engh, a postdoctoral researcher in the Department of Biology at the University of Pennsylvania, added, "After a week or two of moping around, Sylvia suddenly initiated grooming with several low-ranking females. I think that they were as surprised as I was - they seemed awfully nervous at first. Eventually, Sylvia settled into close relationships with a very low-ranking female and with Sierra's daughter, Margaret."
Engh explained to Discovery news that grooming is a friendly behavior where baboons clean each other's fur.
Similar to two human friends chatting over a drink, the activity seems to relax the participants to the point where it can lower stress hormone levels. Those levels rise in humans and baboons after a close friend or relative dies.
The researchers measured a group of such hormones, called glucocorticoids, in Sylvia and 20 other females. Baboons that experienced losses did have elevated levels of the hormones after the deaths.
In humans, this is associated with bereavement, so it is likely that baboons also grieve their dead.
The mourning animals then widened their social circles by approaching and grooming other females, even those that were beneath them in rank. This appeared to help them cope with losses, since stress hormone levels significantly dropped afterwards.
The discovery, outlined in a recent Proceedings of the Royal Society of Biological Sciences paper, underscores the importance of friendship.
"Humans and baboons who are more socially integrated have lower glucocorticoid levels," said Engh. "Both the human research and our results highlight the importance of friendly social relationships in reducing stress."
She added that "females (among baboons) usually have one or two close female friends" that "usually devote a large proportion of their grooming to each other, and they seem to enjoy spending time close together."
Engh also mentioned that friendships form between male and female baboons. For those relationships, the female often grooms the male, while the male protects the female, and any infants that she might have, from predation and bullying baboons.
Brian Craft, lead keeper at the Oakland Zoo in California, told Discovery News that he was not surprised by the findings.
"Advanced relationships are seen in chimpanzees, bonobos, as well as baboons and other multi-social troops," Craft explained.
He said, "Friendships, which may help to ease stress after deaths, can be beneficial to the troop as a whole, as they keep it cohesive. It also appears that friend selection among baboons and other primates is somewhat of a choice, as for humans, and is not just instinctual behavior."
Feb. 10, 2006 - Female baboons that suffer the loss of a close friend or relative turn to other baboons for comfort and support, according to a new study that encompassed 14 years of observing over 80 free-ranging baboons in Botswana's Okavango Delta.
The study provides the first direct evidence that certain animals mourn the loss of individuals, even when the rest of their social group remains intact. The findings also suggest that friendship may be just as important to some primates as it is for humans.
Researchers particularly were struck by the behavior of one female chacma baboon (Papio hamadryas ursinus) named Sylvia, who was described as "the queen of mean" and disdainful of other baboons until she lost her daughter, Sierra, to a lion kill.
"In the week after Sierra died, Sylvia was withdrawn," said Anne Engh, who led the project. "When the other females were grooming and socializing, she tended to sit alone and rarely interacted even with her other relatives."
Engh, a postdoctoral researcher in the Department of Biology at the University of Pennsylvania, added, "After a week or two of moping around, Sylvia suddenly initiated grooming with several low-ranking females. I think that they were as surprised as I was - they seemed awfully nervous at first. Eventually, Sylvia settled into close relationships with a very low-ranking female and with Sierra's daughter, Margaret."
Engh explained to Discovery news that grooming is a friendly behavior where baboons clean each other's fur.
Similar to two human friends chatting over a drink, the activity seems to relax the participants to the point where it can lower stress hormone levels. Those levels rise in humans and baboons after a close friend or relative dies.
The researchers measured a group of such hormones, called glucocorticoids, in Sylvia and 20 other females. Baboons that experienced losses did have elevated levels of the hormones after the deaths.
In humans, this is associated with bereavement, so it is likely that baboons also grieve their dead.
The mourning animals then widened their social circles by approaching and grooming other females, even those that were beneath them in rank. This appeared to help them cope with losses, since stress hormone levels significantly dropped afterwards.
The discovery, outlined in a recent Proceedings of the Royal Society of Biological Sciences paper, underscores the importance of friendship.
"Humans and baboons who are more socially integrated have lower glucocorticoid levels," said Engh. "Both the human research and our results highlight the importance of friendly social relationships in reducing stress."
She added that "females (among baboons) usually have one or two close female friends" that "usually devote a large proportion of their grooming to each other, and they seem to enjoy spending time close together."
Engh also mentioned that friendships form between male and female baboons. For those relationships, the female often grooms the male, while the male protects the female, and any infants that she might have, from predation and bullying baboons.
Brian Craft, lead keeper at the Oakland Zoo in California, told Discovery News that he was not surprised by the findings.
"Advanced relationships are seen in chimpanzees, bonobos, as well as baboons and other multi-social troops," Craft explained.
He said, "Friendships, which may help to ease stress after deaths, can be beneficial to the troop as a whole, as they keep it cohesive. It also appears that friend selection among baboons and other primates is somewhat of a choice, as for humans, and is not just instinctual behavior."