While the mating season varies between the different subspecies, it generally occurs from late spring through fall. About 6 weeks after they give birth to their previous year's pups, the females come into estrus. The gestation period lasts between 9 and 11 months, and usually only 1 pup is born each year. This behavior ends once mating begins. Males initiate behavior by chasing, playfully biting, and embracing females.
Females respond, and the act of copulation usually takes place in the water.
One male may mate with multiple females. Another possible reason for haul outs is protection from predators by being in a group. During haul outs, adult individuals do not make physical contact with each other and respond to touching angrily. Younger seals interact with each other along the edges of the group and stay away from the adults. Aggression is shown by growling, snorting, threateningly waving a foreflipper, and head-thrusting, which is a sharp, rapid retraction of the neck.