Evolutionary explanations for mammalian sociality typically center on inclusive-fitness benefits of associating and cooperating with close kin, or close maternal kin as in some whale societies, including killer and sperm whales. Their matrilineal structure has strongly influenced the thinking about social structure in less well-studied cetaceans, including beluga whales. In a cross-sectional study of group structure and kinship we found that belugas formed a limited number of distinct group types, consistently observed across populations and habitats. Certain behaviours were associated with group type, but group membership was often dynamic. MtDNA-microsatellite profiling combined with relatedness and network analysis revealed, contrary to predictions, that most social groupings were not predominantly organized around close maternal relatives. They comprised both kin and non-kin, many group members were paternal rather than maternal relatives, and unrelated adult males often traveled together. The evolutionary mechanisms that shape beluga societies are likely complex; fitness benefits may be achieved through reciprocity, mutualism and kin selection. At the largest scales these societies are communities comprising all ages and both sexes where multiple social learning pathways involving kin and non-kin can foster the emergence of cultures. We explore the implications of these findings for species management and the evolution of menopause.

哺乳动物社会进化论的解释通常集中在与近亲或某些母鲸亲属（如杀人鲸和抹香鲸）交往或合作的包容性健身益处。它们的母系结构极大地影响了在研究较少的鲸类动物（包括白鲸）中对社会结构的看法。在对群体结构和亲属关系的横断面研究中，我们发现白鹭鸟形成了数量有限的不同群体类型，并在种群和栖息地中得到一致观察。某些行为与组类型有关，但是组成员通常是动态的。与预言相反，MtDNA-微卫星分析与相关性和网络分析相结合，揭示出大多数社会群体并非主要围绕近亲产妇组成。他们包括亲戚和非亲戚，许多小组成员都是父系的，而不是母系的亲戚，无亲属的成年男性经常一起旅行。塑造白鲸社会的进化机制可能很复杂。互惠，互助和亲属选择可以带来健身的好处。在最大程度上，这些社会是一个包括所有年龄段和性别的社区，在这些社区中，涉及亲戚和非亲戚的多种社会学习途径可以促进文化的出现。我们探索这些发现对物种管理和更年期演变的意义。互惠，互助和亲属选择可以带来健身的好处。在最大的规模上，这些社会是一个包括所有年龄段和性别的社区，在这些社区中，涉及亲戚和非亲戚的多种社会学习途径可以促进文化的出现。我们探索这些发现对物种管理和更年期演变的意义。互惠，互助和亲属选择可以带来健身的好处。在最大的规模上，这些社会是一个包括所有年龄段和性别的社区，在这些社区中，涉及亲戚和非亲戚的多种社会学习途径可以促进文化的出现。我们探索这些发现对物种管理和更年期演变的意义。