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Social hair plucking is a grooming convention in a group of captive bonobos (Pan paniscus)


Hair plucking is observed in many captive primate species and is often characterized as an abnormal behavior. However, this behavior may be both self-directed and social and may have different etiologies. Early research in captive macaques (Macaca mulatta) described the aggressive nature of social hair plucking while more recent observations did not find an association with aggression or grooming, but the behavior was initiated most frequently by individuals with more secure dominance rank. Here, we investigate patterns of social hair plucking in a group of captive bonobos at the Columbus Zoo. We tested the hypothesis that social plucking reflects the dominance hierarchy by examining the association between social plucking and grooming, dominance, and kinship. We collected 128 h of grooming data on 16 captive bonobos using all-occurrence sampling. We ran three Mantel tests between a directed grooming matrix and (1) a plucking matrix, (2) a matrix reflecting dominance, and (3) matrix of relatedness. Grooming and hair plucking were significantly correlated (r = 0.25, p < 0.01), however, there was no association between plucking and dominance (r = − 0.04, p = 0.67), or plucking and relatedness (r = 0.07, p = 0.24). These results support the hypothesis that social plucking in bonobos is a grooming convention and is unrelated to dominance.

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We thank the Congo Expedition staff at the Columbus Zoo and Aquarium for their insight and support of this project, particularly Audra Meinelt. We also thank Frances White for recommendations on the data analysis. The manuscript was greatly improved with the suggestions from two anonymous reviewers. This study was approved by the Columbus Zoo and Aquarium. Funding was provided by the Rebecca Jeanne Andrew Memorial Award and the College of Arts and Science Dean’s Scholar Award, Miami University.

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Correspondence to Colin M. Brand.

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Brand, C.M., Marchant, L.F. Social hair plucking is a grooming convention in a group of captive bonobos (Pan paniscus). Primates 60, 487–491 (2019).

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  • Bonobo
  • Pan paniscus
  • Hair plucking
  • Grooming
  • Abnormal behavior
  • Social transmission