"At the time of Sierra's death, we considered Sylvia to be the queen of mean. She is a very high-ranking, 23 year-old monkey who was, at best, disdainful of females other than Sierra," said Anne Engh, a postdoctoral researcher in Penn's Department of Biology. "With Sierra gone, Sylvia experienced what could only really be described as depression, corresponding with an increase in her glucocorticoid levels."
Engh works with Penn biologist Dorothy Cheney and Robert Seyfarth, a professor in Penn's Department of Psychology. For the last 14 years, Cheney and Seyfarth have followed a troop of more than 80 free-ranging baboons in the Okavango Delta of Botswana. Their research explores the mechanisms that might be the basis of primate social relationships and how such relationships may have influenced the development of human social relationships, intelligence and language.
To study the response of stress among baboons, Engh and her colleagues examined the glucocorticoid levels and grooming behavior of females in the troop to see how closely they resemble patterns seen in humans. Their findings were published in a recent article in the Proceedings of the Royal Society of Biological Sciences.
Grooming, a friendly behavior where baboons clean each other's fur, is the primary means by which baboons strengthen social bonds. According to Engh, while the death of a close family member was clearly stressful over the
Contact: Greg Lester
University of Pennsylvania