BIOL 321 Chapter Notes - Chapter 15: Evolutionarily Stable Strategy, Aggression, Glucocorticoid
1 Aug 2017
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Aggression is also called agnostic behaviour and it occurs when animals either send threatening signals and/or engage in some sort of physical combat. When aggression occurs in group-living species, and individuals interact with each other you can measure dominance hierarchies: dominance hierarchies rank orderings of individuals based on the results of pairwise aggressive interactions. Individuals can choose to fight or flee from a potential agnostic opponent. At the ultimate level the choice to fight or flee is choice is based on costs and benefits of aggression. From a proximate perspective, ethologists will focus on the endocrinology underpinnings of aggressive behaviour. Color change is a good communicator in aggressive contest because colour change can quickly indicate an individuals rank in a hierarchy and whether or not it will engage in aggressive behaviour. In atlantic salmon, subordinates assume a much darker body color and the dominates body colour remains light but they develop dark vertical eye bands.
