Agonistic behavior of male southern elephant seals (Mirounga leonina Carnivora: Phocidae) at Isla 25 de Mayo, Antarctica

Abstract

An ethogram is a baseline tool in animal behavioral studies. Nevertheless, for the southern elephant seal (Mirounga leonina Linneo, 1758), a species in which males compete for access to females through agonistic encounters, the ethograms that are being used are based on literature reports, in which behaviors are adapted from other species or only mentioned without being described. As a result, some of the behavioral elements of the species are still unknown. Here we present an ethogram of male agonistic behavior obtained from systematic observations during three consecutive breeding seasons in a rookery situated in the South Shetland Islands, Antarctica. It includes 27 behavioral acts, 6 of which have never been mentioned in the available literature for the species. This ethogram was compared to known behavioral inventories for the species. In addition, the frequencies of occurrence of each behavioral act were obtained for the complete set of observed agonistic interactions. A comparison of the use of each behavioral act by males of different social classes was performed. This allowed to characterize the agonistic behavior of each group during the breeding season.