Overview

In this chapter we outline proximate processes that favour group formation and lead to the emergence of social structure in mammalian societies, particularly complex societies. We operationally define a mammalian society as complex if its social structure includes social coalitions, social alliances or social queues – well known from primates, elephants and cetaceans but also present in, for instance, some carnivores, bats, rodents and ungulates. We consider how social structure can lead to a disparity in the benefits and costs acquired by group members, and how this leads to conflicts of interest between them. We detail the social and reproductive tactics that individuals use when conflicts arise, and consider the fitness consequences associated with these tactics. We illustrate most key points using observational studies of free-ranging mammals, because experimental studies are rare, and we draw examples from a broad range of social systems and mammalian orders.

Introduction

How do complex societies emerge from a life in groups? Living in groups inevitably results in conflicts of interest between group members. The specific forms of these conflicts are likely to affect the strategies to cope with them. Not only will the details of these strategies shape the social relationships we can observe, they may be the consequences of evolutionary processes, and are likely to have resulted in the social complexity described for many mammalian societies.