Chimpanzees act cooperatively in the wild, but whether they afford benefits to others, and whether their tendency to act prosocially varies across communities, is unclear. Here, we show that chimpanzees from neighboring communities provide valuable resources to group members at personal cost, and that the magnitude of their prosocial behavior is group specific. Provided with a resource-donation experiment allowing free (partner) choice, we observed an increase in prosocial acts across the study period in most of the chimpanzees. When group members could profit (test condition), chimpanzees provided resources more frequently and for longer durations than when their acts produced inaccessible resources (control condition). Strikingly, chimpanzees’ prosocial behavior was group specific, with more socially tolerant groups acting more prosocially. We conclude that chimpanzees may purposely behave prosocially toward group members, and that the notion of group-specific sociality in nonhuman animals should crucially inform discussions on the evolution of prosocial behavior.

黑猩猩在野外合作行动，但它们是否能为他人带来利益，以及它们的亲社会行为是否因社区而异，尚不清楚。在这里，我们展示了来自邻近社区的黑猩猩以个人成本为群体成员提供宝贵的资源，并且它们的亲社会行为的程度是特定于群体的。通过允许自由（合作伙伴）选择的资源捐赠实验，我们观察到大多数黑猩猩在整个研究期间的亲社会行为有所增加。当群体成员可以获利时（测试条件），黑猩猩提供资源的频率和持续时间比它们的行为产生不可访问的资源时（控制条件）更频繁。引人注目的是，黑猩猩的亲社会行为是特定群体的，社会宽容度更高的群体表现得更亲社会。