Brand Colin M, Marchant Linda F
Department of Anthropology, University of Oregon, Eugene, Oregon.
Department of Anthropology, Miami University, Oxford, Ohio.
Am J Primatol. 2018 Apr;80(4):e22751. doi: 10.1002/ajp.22751. Epub 2018 Mar 25.
When primates exhibit hair loss and are observed to engage in self or social hair plucking (a rapid jerking away of the hair shaft and follicle by the hand or mouth, often accompanied by inspection, and consumption) the altered appearance, and behavior patterns are thought to reflect individual physiological, and psychological well-being. Hair loss and hair plucking occur in many captive primate species, including all of the great apes. We present the first survey of this behavior among captive bonobos (N = 88; 50 females and 38 males) in seven zoos in the United States. We found that 43% of the population engaged in this behavior pattern and discounting youngsters (who are not observed to hair pluck until the age of five), 58% of individuals hair plucked. Of the individuals who hair plucked, 97% engaged in social plucking, whereas 46% engaged in self-directed plucking. We regressed the occurrence of hair plucking with multiple predictor variables using binary logistic regression and multimodel inference to determine which predictors best explained the prevalence of self-directed and social plucking. We also analyzed publicly available data on hair plucking in captive chimpanzees. We found that the occurrence of another abnormal behavior, age, origin, and pelage condition best explained self-directed plucking in bonobos. Social plucking was explained by age, origin, pelage, and sex. Our analysis of chimpanzee hair plucking revealed that plucking is strongly influenced by rearing and sex. This study demonstrates that hair plucking is more prevalent in captive bonobos compared to captive chimpanzees and gorillas, however, the covariates associated with hair plucking for each species are different. Our data suggest a potential link between self-directed plucking and well-being. However, the higher prevalence and etiology of social hair plucking is more difficult to explain.
当灵长类动物出现毛发脱落，并被观察到有自我或社交性拔毛行为（通过手或嘴快速揪掉毛干和毛囊，常伴有查看和吞食行为）时，其外观和行为模式的改变被认为反映了个体的生理和心理健康状况。毛发脱落和拔毛现象在许多圈养灵长类物种中都有发生，包括所有的大型猿类。我们首次对美国7家动物园中圈养的倭黑猩猩（N = 88；50只雌性和38只雄性）的这种行为进行了调查。我们发现，43%的群体有这种行为模式，不考虑幼崽（直到5岁才观察到有拔毛行为），58%的个体有拔毛行为。在有拔毛行为的个体中，97%有社交性拔毛行为，而46%有自我导向性拔毛行为。我们使用二元逻辑回归和多模型推断，将拔毛行为的发生情况与多个预测变量进行回归分析，以确定哪些预测因素能最好地解释自我导向性拔毛和社交性拔毛的普遍程度。我们还分析了圈养黑猩猩拔毛行为的公开可用数据。我们发现，另一种异常行为的发生情况、年龄、来源和皮毛状况最能解释倭黑猩猩的自我导向性拔毛行为。社交性拔毛行为则由年龄、来源、皮毛和性别来解释。我们对黑猩猩拔毛行为的分析表明，拔毛行为受饲养方式和性别的强烈影响。这项研究表明，与圈养黑猩猩和大猩猩相比，拔毛行为在圈养倭黑猩猩中更为普遍，然而，与每个物种拔毛行为相关的协变量是不同的。我们的数据表明自我导向性拔毛与健康状况之间可能存在联系。然而，社交性拔毛行为较高的发生率和病因更难解释。
