Department of Anthropology, Miami University
Thursday All day, Clinch Concourse
Both wild and captive studies of grooming in non-human primates emphasize the adaptive role of this behavior. Indeed, social grooming is frequently characterized as “social glue” in the life of primates. In captivity, grooming behavior is studied to reveal dominance, kin relations, and social networks. Unfortunately, many captive primates, including apes, are observed to over-groom which may result in denuding of individuals. This study focused on a discrete pattern of grooming, specifically plucking - a rapid jerking away of the hand or mouth to remove the hair follicle, often accompanied by inspection and consumption. This pattern has never been reported for wild bonobos but is routinely observed in many individuals in captive colonies. Subjects were 17 bonobos (4 wild-born and 13 captive-born) housed at the Columbus Zoo. Data were collected using focal behavior sampling, all-occurrence. Results of time-budget analyses show that approximately 21% of self-directed and dyadic-grooming bouts involved hair plucking. The four wild-born individuals were never observed to hair pluck. Age class strongly influenced the percent of grooming bouts that involved plucking - for adolescents the mean percent of grooming bouts involving plucking was 38.5%, whereas in adults it was 20%. Self-directed plucking appears to be influenced by dominance in that the dominant male and female showed the highest percent of self-directed plucking behavior, 54% and 57% respectively. This is the first study to document the significance of plucking in bonobo grooming behavior and contributes to discussions of visitors’ perception of ape well being.
Rebecca Jeanne Andrew Memorial Award, Miami University