The establishment and maintenance of dominance hierarchies

Abstract

Animal groups are often organized hierarchically, with dominant individuals gaining priority access to resources and reproduction over subordinate individuals. Initial dominance hierarchy formation may be influenced by multiple interacting factors, including an animal's individual attributes, conventions and self-organizing social dynamics. After establishment, hierarchies are typically maintained over the long-term because individuals save time, energy and reduce the risk of injury by recognizing and abiding by established dominance relationships. A separate set of behaviours are used to maintain dominance relationships within groups, including behaviours that stabilize ranks (punishment, threats, behavioural asymmetry), as well as signals that provide information about dominance rank (individual identity signals, signals of dominance). In this review, we describe the behaviours used to establish and maintain dominance hierarchies across different taxa and types of societies. We also review opportunities for future research including: testing how self-organizing behavioural dynamics interact with other factors to mediate dominance hierarchy formation, measuring the long-term stability of social hierarchies and the factors that disrupt hierarchy stability, incorporating phenotypic plasticity into our understanding of the behavioural dynamics of hierarchies and considering how cognition coevolves with the behaviours used to establish and maintain hierarchies. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Keywords: aggression; contests; dominance relationships; resource holding potential; social instability; social structure.

Figure 1.

Mechanisms involved in establishing and maintaining dominance hierarchies. Establishing dominance. Individual attributes are traits such as RHP and/or motivation, assessed via aggressive interactions, signals of fighting ability and social information (e.g. claw waving displays provide information about fighting ability during contests between rival crabs [22]). Conventions are unique attributes that single out an individual as the next dominant without reflecting intrinsic characteristics that allow individuals to win contests (e.g. maternal rank inheritance in baboons [23]). Self-organizing social dynamics are social processes at the group level that increase hierarchy linearity (e.g. fishes that interact in groups are more likely to form transitive dominance relationships than fishes that only interact in dyadic contests [14]). Maintaining dominance. Signals of dominance provide information about dominance rank (e.g. dominant ant queens have cuticular hydrocarbons that provide information about rank and influence queen/worker interactions [24]). Signals of individual identity are unique phenotypes that receivers learn and associate with individual-specific information about the sender like dominance rank. (e.g. Polistes fuscatus wasps learn the dominance rank of individuals via aggressive contests and social eavesdropping and associate rank information with the unique facial patterns of conspecifics [25,26]). Behavioural mechanisms help dominants maintain their rank like threats, punishment and self-reinforcing behavioural mechanisms (e.g. in meerkats, dominants aggressively evict subordinates that try to reproduce [27]. (Online version in colour.)

Figure 2.

Three common ways animals assess the individual attributes of conspecifics. (a) Signals of fighting ability. Platysaurus broadleyi signal fighting ability with UV throat coloration [31]. (b) Competitive interactions. Panthera leo fight with rivals. (c) Social information. Xiphophorus helleri gain information about the fighting ability of potential rivals by observing and remembering how conspecifics behave during contests with other individuals [32]. (Online version in colour.)

Figure 3.

Signals involved in dominance hierarchy establishment and maintenance. (Online version in colour.)