Social behaviuor between adult male and female New Zealand fur seals, Arctocephalus forsteri (Lesson) during the breeding season

Abstract

Observations on social relations between territorial adult male and adult female A. forsteri were made on the Open Bay Islands, Westland, New Zealand, during the breeding season 1970-71. Threats comprised about 80% of all social encounters between males and females. Attempted and successful olfactory investigations of females by males, herding of females by males, and 'peace-keeping' by males accounted for about 18% of all encounters, and such interactions usually had agonistic overtones. Less than 2% of all encounters were not agonistic from their inception. Herding responses of males were vigorous and frequent, and are interpreted as serving two functions: containment of females and communication of certain of the herding males' characteristics to the females. Because herding occurs throughout the Otariidae, and is rarely effective in containing females, the second function is probably more important. Males showed much individual variation in their herding tendencies. The frequency of herding behaviour was depressed at warm temperatures. Olfactory investigations of facial and perineal regions of females were common and were not restricted to peri-oestrous females. Only oestrous females were sexually receptive to and showed little aggression toward territorial males, and males detected their physiological state mainly through olfaction. A few oestrous females solicited males with mock threats or by rubbing against them. Precopulatory and early copulatory behaviour was characterized by a moderate amount of mutual contact-seeking behaviour, multiple mounts by the male, and 'activation' of the female by the male biting her. Copulations appeared to be terminated through physical resistance by the female, which resulted in ejaculation and subsequent dismounting by the male. At the time of female resistance, the male commonly had to physically control her. The sudden return to aggressive behaviour typical of non-oestrous females may be mediated through a neural inhibitory process resulting from cervico-vaginal stimulation, as has been proposed for the guinea pig.