Dominance (animal behavior)
For dominance in genetics see Dominance (genetics)
Dominance in animal behavior refers to an "individual's preferential access to resources over another." The opposite of dominance is submissiveness, where one or more other individuals, react submissively to dominant individuals. The dominant individuals within a group obtain preferential access to resources such as food or potential mates at the expense of the submissive individuals, often without active aggression. The absence or reduction of aggression means unnecessary energy expenditure and the risk of injury are reduced for both.
Dominance may be a purely "two way" (dyadic) relationship, i.e. individual A is dominant over individual B, but this has no implications for whether either of these is dominant over a third individual C. Alternatively, dominance may be hierarchical, with a transitive relationship, so that if A dominates B and B dominates C, A always dominates C. This is called a linear dominance hierarchy. Some animal societies have despots, i.e. a single dominant individual with little or no hierarchical structure amongst the rest of the group. Horses use coalitions so that affiliated pairs in a herd have an accumulative dominance to displace a third horse that normally out-ranks both of them on an individual basis.
Dominance–subordination relationships can vary markedly between breeds of the same species. Studies on Merino sheep and Border Leicesters sheep revealed an almost linear hierarchy in the Merinos but a less rigid structure in the Border Leicesters when a competitive feeding situation was created.<ref name="Squires and Daws, (1975)"/>
Dominance in Various Species
Referred to as the pecking order, dominance hierarchies in chickens is asserted by various behaviours, including pecking, which was used by Schjelderup-Ebbe as a measure of dominance and leadership order in his 1924 German-language article. He noted that "defense and aggression in the hen is accomplished with the beak". This emphasis on pecking led many subsequent studies on fowl behaviour to use it as a primary observation, however, it has been noted that roosters tend to leap and use their claws in conflicts.