Agonistic Encounters Among Male Elephant Seals: Frequency, Context, and the Role of Female Preference

Abstract

SYNOPSIS. Aggressive interactions between male northern elephant seals, Mirounga angustirostris, observed during the course of three breeding seasons are analyzed from the perspective of costs and benefits to individuals. Males spend less than one percent of their time in aggressive activities and the overwhelming majority of agonistic interactions consist only of visual and vocal threats rather than physical combat. Males are most likely to threaten other males when the likelihood that they will be successful in displacing the opponent is high. Males who are mounting females, or who are in close proximity to females, are threatened more frequently than males who are otherwise occupied. However, high ranking bulls do regularly issue threats which are not provoked by the location or behavior of the recipient. Despite the obvious costs of such threats, this behavior may be favored as a result of female choice. Estrous females are more receptive when mounted by a male who has just dominated another than when mounted by a male of similar rank who has been resting or recently displaced by a stillmore dominant male. A general argument is made that in species where social status of males is correlated with their genetic fitness, female choice is likely to be based on social signals which are used incompetition between males.