Socially inflicted traumas are a major concern for the management of captive groups of rhesus macaques. Rhesus macaques are the most commonly used nonhuman primate in biomedical research, and social housing is optimal for promoting psychological well-being. However, trauma is frequent due to a strong reliance on aggression to establish and maintain hierarchical relationships. We studied six captive groups of rhesus macaques (Macaca mulatta) that underwent a variety of social perturbations and explored whether rates of aggression mapped onto rates of trauma using a fine-grained analysis that divided both aggression and trauma variables into specific, behaviorally-relevant categories (e.g., severe aggression by adult males relative to lacerations). Results did not show the expected positive relationship between aggression variables and trauma variables. Instead, rates of trauma (i.e., lacerations, moderate-severe trauma, total trauma) were negatively associated with the rate of impartial interventions (i.e., an intervention directed at both targets during an ongoing conflict) during baseline periods. Additionally, rates of trauma (i.e., lacerations, punctures, moderate-severe trauma, total trauma) were negatively associated with rates of total aggression following temporary knockouts of the individuals who commonly intervene impartially (i.e., conflict policers), and punctures and moderate-severe trauma were negatively associated with rates of severe aggression by adult males following permanent knockout of a high-ranked natal male. These results suggest that under homeostatic conditions, impartial interventions serve as a mechanism to reduce socially inflicted trauma but, following social manipulations of high-ranking males, an imbalance emerges. Our results underscore the importance of developing management strategies for rhesus macaque groups that promote internal social mechanisms of social stability such as maintaining conflict policing individuals (i.e., adult males) in social groups.

中文翻译：

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高攻击率并不能预测圈养猕猴的创伤率

社会造成的创伤是管理圈养恒河猴群体的主要问题。恒河猴是生物医学研究中最常用的非人类灵长类动物，社会住房是促进心理健康的最佳选择。然而，由于强烈依赖侵略来建立和维持等级关系，创伤很常见。我们研究了六组圈养恒河猴（Macaca mulatta），它们经历了各种社会扰动，并使用细粒度分析将攻击性和创伤变量分为特定的、行为相关的类别，探索攻击率是否映射到创伤率（例如，成年男性相对于撕裂伤的严重攻击）。结果没有显示攻击变量和创伤变量之间预期的正相关关系。相反，在基线期间，创伤率（即撕裂伤、中重度创伤、总创伤）与公正干预（即在持续冲突期间针对两个目标的干预）率呈负相关。此外，创伤率（即撕裂伤、刺伤、中度至重度创伤、总创伤）与临时击倒通常公正干预的个体（即冲突警察）以及刺伤和中度创伤后的总攻击率呈负相关。严重创伤与成年男性在永久性击倒高等级出生男性后的严重攻击率呈负相关。这些结果表明，在稳态条件下，公正的干预是一种减少社会造成的创伤的机制，但在对高级男性进行社会操纵之后，就会出现不平衡。我们的研究结果强调了为恒河猴群体制定管理策略的重要性，这些策略可以促进社会稳定的内部社会机制，例如在社会群体中维持冲突警务人员（即成年男性）。