The brown fur seal belongs to a large seal species from Australia and South Africa. Adult males are light grayish-brown with a dark brown belly, and a mane around the neck and shoulders that becomes a lighter color as they age. The female is browner, but still has a darker brown belly. The adult male's head is larger and wider than the female's, with a low brow, which the female does not have. Both males and females have a pointed snout, long whiskers, small ears, and forward-facing nostrils. They have large, thick flippers, which look black when wet. There are two subspecies of the brown fur seal: the Cape fur seal and the Australian fur seal. These subspecies are behaviorally and genetically very similar, but they occupy distinct ranges. One clear difference between them is the larger crest of the Cape fur seal.
Cape fur seals are found along the coast of Africa in the south and southwest, throughout Namibia and to the east as far as Port Elizabeth, while the Australian fur seal occurs along Australia's southern and southeastern coasts. They are seen in New South Wales, Victoria, Tasmania and certain islands. Both subspecies spend the majority of their time at sea, not too far from the coast. They prefer small rocky islands when mating and giving birth.
Brown fur seals are diurnal, being active during the daytime and sleeping at night. Groups that share the same rookery every year are known as colonies. Colonies of South African fur seals range in number between 500 and 3,000 bulls, and the size of Australian fur seal colonies ranges from 500-1,500 animals. These seals don’t migrate and the rookeries are never completely empty, as the mothers and pups come back to them during the year. Most of the time, however, the seals are at sea, where they often travel in feeding groups of a small size. There are no real boundaries between colonies, since throughout the year they all travel separately until the breeding season.
These seals are polygynous, but the females are not herded by the males, and are free to select their own mates, and they do so according to the value of their territories. They start to breed in mid-October when males come to shore to establish their territories though vocalizations, display and sparring, sometimes leading to combat. They fast at this time, not eating until after mating later in November or December. The females then arrive, and fight among themselves for birthing territories. After a gestation of 12 months, including some months of delayed implantation (when the embryo, rather than developing, is maintained in a dormant state, which lengthens the normal gestation period), a single pup is born. Females will then spend brief periods foraging at sea, then several days on shore nursing their pups. In winter, foraging trips last around seven days, and in summer and autumn about four days. Pups are weaned around the age of 12 months, and sexual maturity is reached at 3 - 6 years of age.
The greatest threat to brown fur seals is pollution of their habitat with heavy metals, pesticides and noise disturbance. Oil spills, pieces of netting, plastic, and fishing lines are also a threat, killing or injuring thousands of these seals a year. Poaching is a further threat: they have been seen taking fish from nets, occasionally becoming tangled up and drowning, and sometimes fur seals are shot illegally by fishermen as a way of reducing competition for stocks of fish.
According to the IUCN Red List, the total number of brown fur seals is 2,120,000 individuals, being 2,000,000 Cape fur seals and 120,000 Australian fur seals. Overall, the brown fur seal population numbers are increasing today, and this species is classified as least concern (LC).