Due to its limited mobility on land, the Subantarctic fur seal carefully selects islands with few or no predators upon which to breed (6). Although the first breeding males arrive on land in late October, with the females following a short while later, the bulk of breeding takes place in December (1) (10) (11). Only the territorial males and mature females congregate on established breeding grounds, with immature seals, and the smaller males without territories, gathering on peripheral grounds. Breeding beaches are often heavily crowded, with the females grouping around the more evenly spaced territorial males. The bulls defend their territories from rival males and although fighting rarely goes beyond display and threats, on the occasions that it does, fighting may ensue, often with life-threatening wounds inflicted upon the defeated bull (2) (6). Successful males gather a harem of usually 6 to 8 females and will breed with each female (2).
Those females that mated the previous season will give birth to a single pup, after a gestation period of almost a year, within 6 days after coming ashore before mating 8 to 12 days later. Mothers stay with the newborn pup for around a week before returning to the sea to feed, returning 6 to 10 days later to feed their pup. Thereafter, the adult female undergoes a regular cycle of several days ashore with their pups followed by several weeks at sea foraging until the pup is weaned at an approximate age of 11 months. While the pups grows quickly on the energy-rich milk of its mother, and will start to swim in rock pools and shallows after six weeks, it will first go to sea after weaning (1) (2) (4) (7) (10) (11) (12) (13).
Juvenile seals often venture far away from the breeding islands, with some individuals travelling many thousands of kilometres to feed as far away as off the coast of South America and South Georgia Island (2). Very little is known of the behaviour of the Subantarctic fur seal while at sea, but they feed largely on fish, to a lesser extent squid, occasionally krill and very occasionally penguins (2) (5). Using its modified eyes and vibration-sensitive whiskers, this seal is thought to actively seek out its prey, with most dives taking place at night-time when many fish species migrate towards the ocean’s surface (6) (8).