Data from: Not just females: the socio-ecology of social interactions between spider monkey males

Male-male relationships are mostly characterized by competition. However, males also cooperate with one another if socio-ecological conditions are suitable. Due to their male philopatry, need for cooperation in home range defence and high degree of fission-fusion dynamics, spider monkeys provide an opportunity to investigate how male-male interactions are associated with socio-ecological factors, such as the presence of potentially receptive females, the degree of food availability and the likelihood of home range defence. We tested predictions about changes in social interactions between wild spider monkey males in relation to these factors. First, males did not change their interaction patterns when potentially receptive females were in the subgroup compared to when they were absent. Second, males tended to be less tolerant of one another when feeding, but spent more time grooming, in contact and proximity with one another when food availability was lower than when it was higher. Third, males exchanged fewer embraces, spent less time grooming, in proximity and in contact with one another, and spent more time vigilant at the home range boundary area than at other locations. Our findings contribute to the understanding of social flexibility and the importance of considering males in socio-ecological models of any group-living species.雄性个体间的关系大多以竞争为核心特征，但当社会生态条件适宜时，雄性之间也会开展合作行为。鉴于蜘蛛猴具有雄性恋巢性（male philopatry）、存在家域（home range）防御的合作需求，且具备高度的裂变-融合动态（fission-fusion dynamics）特征，该物种为探究雄性间互动与社会生态因素的关联提供了绝佳研究机会——这些社会生态因素包括潜在可接受交配的雌性的存在、食物可获得性程度，以及家域防御的可能性。本研究针对野生雄性蜘蛛猴的社交互动如何随上述因素变化提出多项预测，并逐一开展验证。其一，当临时亚群中存在潜在可接受交配的雌性时，雄性的互动模式与雌性缺席时并无显著差异。其二，雄性在取食时彼此的容忍度往往更低；而当食物可获得性较低时，它们会花费更多时间互相理毛、进行身体接触并保持空间亲近，反之则情况相反。其三，相较于家域内其他区域，雄性在家域边界地带的拥抱互动更少，理毛、空间亲近与身体接触的时长更短，而用于警戒的时间则更长。本研究结果有助于深化对社交灵活性的认知，同时也凸显了在任何群居物种的社会生态模型中纳入雄性个体视角的重要性。