title: Sexual harassment and female gregariousness in the South American sea lion, Otaria flavescens.
abstract: Most colonial pinnipeds form extreme clusters of breeding females that cannot be entirely explained by the distribution of sites for reproduction. Avoidance of male harassment has been postulated as an important determinant of reproductive aggregation in this group of mammals. Female gregariousness can reduce harassment by resident males by two mechanisms; directly by the 'dilution effect' or indirectly because resident males that defend large female groups are less harassing. In order to investigate the relationship between male harassment and female gregariousness in relation to the size of breeding groups, we analysed the behaviour of dominant males and their females in a breeding colony of Otaria flavescens. Females in large breeding groups received less harassment by resident males due to dilution effects and because males that defended a large group interacted less frequently with females than males with small groups.
authors.affiliation: Estación Hidrobiológica de Puerto Quequén y Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN-CONICET), Av. Angel Gallardo 470, C1405DJR, Buenos Aires, Argentina.
authors.forename: Humberto L
authors.initials: HL
authors.lastname: Cappozzo
authors.forename: Juan I
authors.initials: JI
authors.lastname: Túnez
authors.forename: Marcelo H
authors.initials: MH
authors.lastname: Cassini
mesh_terms: D000374:Aggression; D000818:Animals; D001118:Argentina; D001947:Breeding; D005260:Female; D008297:Male; D012044:Regression Analysis; D012098:Reproduction; D046070:Sea Lions / Q000502:physiology*; D012726:Sexual Behavior, Animal; D012919:Social Behavior; D012930:Social Dominance