Animal societies are shaped both by social processes and by the physical environment in which social interactions take place. While many studies take the observed patterns of inter-individual interactions as products and proxies of pure social processes, or as links between resource availability and social structure, the role of the physical configuration of habitat features in shaping the social system of group-living animals remains largely overlooked. We hypothesise that by shaping the decisions about when and where to move, physical features of the environment will impact which individuals more frequently encounter one another and in doing so the overall social structure and social organization of populations. We first discuss how the spatial arrangement of habitat components (i.e. habitat configuration) can shape animal movements using empirical cases in the literature. Then, we draw from the empirical literature to discuss how movement patterns of individuals mediate the patterns of social interactions and social organization and highlight the role of network-based approaches in identifying, evaluating and partitioning the effects of habitat configuration on animal social structure or organization. We illustrate the combination of these mechanisms using a simple simulation. Finally, we discuss the implications of habitat configuration in shaping the ecology and evolution of animal societies and offer a framework for future studies. We highlight future directions for studies in animal societies that are increasingly important in widely human-modified landscapes, in particular the implications of habitat-driven social structure in evolution. Significance statement There is now clear evidence that simple processes can generate apparent complex patterns of social structure. However, while studies such as those on collective behaviour and social networks have been focused on processes involving individual decisionmaking, broader patterns of social structure and social organization can also be shaped by factors that have more fundamental impacts on the movements of animals. One set of those factors is related to the amount and spatial arrangement of both biotic and abiotic components of the habitat in which animals live. Examples include the configuration formed by habitat patches connected through corridors, by the presence of hard boundaries between habitat types or by the uneven distribution of resources, mates and competitors across space. In this contribution, we highlight the potential effects of these, which are becoming increasingly important as studies start being able to track populations spanning larger landscapes.

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Variation in extra-pair paternity (EPP) among individuals of the same population could result from stochastic demography or from individual differences in mating strategies. Although the adaptive value of EPP has been widely studied, much less is known about the characteristics of the social environment that drive the observed patterns of EPP. Here, we demonstrate how concepts and well-developed tools for the study of social behaviour (such as social network analysis) can enhance the study of extra-pair mating decisions (focussing in particular on avian mating systems). We present several hypotheses that describe how characteristics of the social environment in which individuals are embedded might influence the levels of EPP in a socially monogamous population. We use a multi-level social approach (Hinde, 1976) to achieve a detailed description of the social structure and social dynamics of individuals in a group. We propose that the pair-bond, the direct (local) social environment and the indirect (extended) social environment, can contribute in different ways to the variation observed in the patterns of EPP, at both the individual and the population level. A strength of this approach is that it integrates into the analysis (indirect) interactions with all potential mates in a population, thus extending the current framework to study extra-pair mating behaviour. We also encourage the application of social network methods such as temporal dynamic analysis to depict temporal changes in the patterns of interactions among individuals in a group, and to study how this affects mating behaviour. We argue that this new framework will contribute to a better understanding of the proximate mechanisms that drive variation in EPP within populations in socially monogamous species, and might ultimately provide insights into the evolution and maintenance of mating systems.