Cooperation-based concept formation in male bottlenose dolphins

In Shark Bay, Western Australia, male bottlenose dolphins form a complex nested alliance hierarchy. At the first level, pairs or trios of unrelated males cooperate to herd single females. Multiple first-order alliances cooperate in teams (second-order alliances) in the pursuit and defense of females, and multiple teams also work together (third-order alliances). Yet it remains unknown how dolphins classify these nested alliance relationships. We used 30 years of behavioural data combined with 40 contemporary sound playback experiments to 14 allied males, recording responses with drone-mounted video and a hydrophone array. We show that males form a first-person social concept of cooperative team membership at the second-order alliance level, independently of first-order alliance history and current relationship strength across all three alliance levels. Such associative concepts develop through experience and likely played an important role in the cooperative behaviour of early humans....

在澳大利亚西部的鲨鱼湾（Shark Bay），雄性宽吻海豚会形成一套复杂的嵌套式联盟层级结构。在第一层级中，无亲缘关系的雄性个体以成对或三人组的形式协作围捕单个雌性海豚。多个一级联盟（first-order alliance）会以团队形式开展合作，即二级联盟（second-order alliance），用于追捕与守护雌性海豚；而多个二级联盟也会协同行动，形成三级联盟（third-order alliance）。然而目前人们仍不清楚海豚如何对这类嵌套式联盟关系进行分类。本研究整合了30年的行为学数据与40项针对14只结盟雄性海豚的当代声回放实验，通过挂载于无人机的摄像设备与水听器阵列（hydrophone array）记录受试个体的反应。研究结果表明，雄性海豚会形成针对二级联盟层级中合作团队成员身份的第一人称社会认知（first-person social concept），且该认知独立于一级联盟的过往互动历史与当前关系亲疏，覆盖全部三个联盟层级。这类联想性认知概念通过后天经验发展而来，且极有可能在早期人类的合作行为中发挥了重要作用……