Summary Family living is an important aspect of social behaviour in species throughout the animal kingdom. The organisation of family groups varies across species, from simple family life, such as that where offspring are tolerated on the parental territory, to highly complex family structures, such as that found in eusocial insects. This variation has captivated behavioural and evolutionary biologists for decades. As a result, there has been substantial work to explain how complex family organisation comes about in the first place. Family living initially arises when offspring forgo immediate dispersal, for instance due to ecological constraints (e.g., no available territories), and remain with one or both parents instead. Kin selection is thought to play an important role in this group formation through the inclusive fitness benefits provided by cooperating with related conspecifics. An implicit assumption to preferential cooperation with kin is that individuals recognise their relatives, a process called kin recognition. Nevertheless, the precise relationship between kin recognition and the evolution of family organisation, as well as the factors that have influenced the emergence of kin ecognition itself, remain largely unknown.
