One-fur sealions have a rather complex social structure. When the breeding season arrives, the males arrive at the beaches and establish themselves in a small section of the rocky coast, marking the territory for their harem and keeping other males at bay.
The females, who were impregnated the previous year and are in the final stage of gestation, will then arrive. They will gather around an adult male, joining his harem. Remaining in the harem is very beneficial for the females because once the offspring is born, the female will have to go to the sea in search of food and then return to nurse the protected pup within the group. Furthermore, a dominant male ensures strength that will be passed on to the genes of the future offspring. Just five or six days after giving birth, the female enters her one-day-long estrus period, during which she will mate and become pregnant again. During this time, the fights among the males are constant, as they attempt to dethrone the “sultan” and take control of his females.
It is normal, then, for sexually active but not yet dominant juvenile males to gather in the vicinity of the harem area. These juveniles are constantly on alert for any movements by the females. When the females leave the harem to go to the sea for refreshment or to find food, the juveniles see an opportunity to kidnap and take them to a secluded area on the beach. The female will resist and try to return to the safety of the harem, but she will be subdued through pushing and biting. Considering that an adult male can measure 2.3 meters in length and weigh 300 kg, it is normal for him to dominate a female measuring 1.8 meters and weighing 140 kg.
The raptor will wait until the time of birth to try to impregnate the female when she enters estrus. Often, the newborn pup dies at the hands of the raptor or another subadult male who has not acquired a female. Occasionally, kidnappings have been observed months before the birth. In such cases, the juvenile males may be attempting to form their own harem. However, since no one can be on guard twenty-four hours a day for an extended period, the female has a great chance of escaping and returning to the safety of the group. Meanwhile, the young sea lion must wait to grow and establish his own harem or wait for another solitary female to attempt a new abduction.
“You cannot defend what you do not love, and you cannot love what you do not know.”