SEXUAL BEHAVIOR OF MALE NORTHERN ELEPHANT SEALS: II. FEMALE RESPONSE TO POTENTIALLY INJURIOUS ENCOUNTERS

[During mating attempts by males, female elaphant seals, Mirounga angustirostris, are sometimes injured or killed as they return to sea at the end of lactation. We tested two predictions from the general hypothesis that females behave in a way that reduces the possibility of injury or death from sexual encounters with males: 1) departing females attempt to avoid males, and 2) if males cannot be avoided, departing females exhibit sexually receptive behavior to males, and thereby reduce the threat of injury from aggressive mating attempts. Circumstances surrounding the departure of 336 females from harems on the Ano Nuevo rookery in central California were recorded over the course of nine breeding seasons from 1982-1990. Females did little to avoid encounters with males surrounding harems; they did not leave in greater numbers at night, in groups, or during disturbances on the harem periphery. They did, however, leave harems preferentially at high tide which reduced the distance to the water and shortened transist time. Most departing females did not resist the mating attempts of peripheral males but, rather, they were unusually receptive. Receptive females received fewer blows capable of producing injury than resisting females. We conclude that receptive behavior in this context "buys safe passage". It is an effective means of reducing male aggression and the probability of injury; a male has no need to restrain a receptive female with blows, and should the most dominant male in the area copulate with a departing female, he frequently escorts her to sea and defends her from other males., During mating attempts by males, female elaphant seals, Mirounga angustirostris, are sometimes injured or killed as they return to sea at the end of lactation. We tested two predictions from the general hypothesis that females behave in a way that reduces the possibility of injury or death from sexual encounters with males: 1) departing females attempt to avoid males, and 2) if males cannot be avoided, departing females exhibit sexually receptive behavior to males, and thereby reduce the threat of injury from aggressive mating attempts. Circumstances surrounding the departure of 336 females from harems on the Ano Nuevo rookery in central California were recorded over the course of nine breeding seasons from 1982-1990. Females did little to avoid encounters with males surrounding harems; they did not leave in greater numbers at night, in groups, or during disturbances on the harem periphery. They did, however, leave harems preferentially at high tide which reduced the distance to the water and shortened transist time. Most departing females did not resist the mating attempts of peripheral males but, rather, they were unusually receptive. Receptive females received fewer blows capable of producing injury than resisting females. We conclude that receptive behavior in this context "buys safe passage". It is an effective means of reducing male aggression and the probability of injury; a male has no need to restrain a receptive female with blows, and should the most dominant male in the area copulate with a departing female, he frequently escorts her to sea and defends her from other males.]