Group Raids: A mating strategy of male southern sea lions.

CAMPAGNA, C.; LE BOEUF, B. J.; CAPPOZZO, H.L

BEHAVIOUR

Brill Academic Publishers

Lugar: Leiden; Año: 1988 vol. 105 p. 224 - 249

0005-7959

Southern sea lions, Otaria byronia, breed in a narrow zone along the high tide mark where males sequester females, defending them against competitors that congregate on the periphery. During four breeding seasons, 15 December to 10 February, 1983-1986, we observed marked animals at Punta Norte, Peninsula Valdes, Argentina, and recorded the form, frequency and consequences of an unusual mating strategy: groups of males raid the breeding area attempting to seize females from resident, territorial males. Raids were often triggered by one male rushing into the breeding area. Females fled from the point of attack and were separated from their pups and were redistributed within the breeding area. Some resident males gained females, other were deposed and lost females, while some raiders gained females and residency in the breeding area. Group raids consist of a collective revolt against the status quo, similar in for to troop takeovers by groups of male hanuman langurs. Outside males can achieve proximity to oestrous females with less risk of injury by raiding in a group rather than attempting to seize a female by themselves