Brown fur seal
The brown fur seal (Arctocephalus pusillus), also known as the Cape fur seal, South African fur seal and the Australian fur seal) is a species of fur seal.
The brown fur seal has a large broad head and a pointed snout. Males are brown to dark gray with a darker mane and a light underside. They grow up to 2.2m (7ft) and weigh around 200-360 kg (440-800lb). Females are gray to light brown with a dark underside and light throat. They grow up to 1.7m (5ft) and weigh on average 120kg (260lbs). Pups are black at birth, but turn gray with a pale throat after molting. They are capable of diving to a depth of 600 meters (2000ft).
Distribution and habitat
The brown fur seal is found along the coast of Namibia and along the west coast of South Africa to the Cape of Good Hope and the Cape Province. Its Australian subspecies (Arctocephalus pusillus doriferus) breeds on nine islands in the Bass Strait between Tasmania and Victoria.
Both subspecies mostly haul out and breed on rocky islands, rock ledges or reefs and pebble or boulder beaches. South African fur seals (Arctocephalus pusillus pusillus) have large breeding sites on sandy beaches in South Africa, and a nonbreeding group regularly hauls out on a sandy beach in Cape Fria in northern Namibia.
Brown fur seals feed mostly on bony fish, as well as cephalopods, crustaceans and even birds. The Australian subspecies forages at the bottom of the continental shelf, while the African subspecies forages in the open ocean.
Behavior and reproduction
Although they normally travel alone, large groups of these seals can be seen rafting in kelp beds. Pregnant females will stay away from the land for seven weeks before the breeding season.
Brown fur seals breed in mid-October. Unlike many eared seal species, a female is free to choose her mate, and he is judged based on the value of his territory. Both males and females fight for territories with individuals of the same sex. Females have smaller territories and a male's territory may overlap that of several females. A harem may consist of 50 females for one male.
Pups are usually born between late November and early December. After they are born, the females start to mate with their harem leaders. The female spends the next several months foraging at sea and nursing her pup, who is weaned at four months old. The pups begin swimming at an early age and the time they spend in the water increases as the pup learns more. By seven months, the pup can swim for two to three days at a time.
The brown fur seal's main predator is the great white shark, although they are also preyed upon by various other animals as well, such as orcas. Land-based predators include black-backed jackals and brown hyenas on the Skeleton Coast in Namibia.
In False Bay, the seals employ a number of antipredatory strategies while in shark-infested waters such as:
- Swimming in large groups
- Low porpoising to increase subsurface vigilance
- Darting in different directions to cause confusion when attacked
- Riding near the dorsal fin to keep out of reach of the shark's jaws when attacked.
This species is an inquisitive and friendly animal when in the water, and will often accompany SCUBA divers. They will swim around divers for periods of several minutes at a time, even at a depth of 60m. On land, they are far less relaxed and tend to panic when people come near them.
Australian fur seals were hunted intensively between 1798 and 1825 for commercial reasons. Seal hunting stopped in Australia in 1923, and their population is still recovering. Breeding and haul-out sites are protected by law. The Tasmanian government authorized the killing of "nuisance" fur seals, however, in October 2000.
South African fur seals have a very robust and healthy population. Harvesting of seals was outlawed in South Africa in 1990.
Brown fur seals are still harvested in Namibia. Around 85,000 pups a year are clubbed to death; their fur is bought by Turkish businessman Hatem Yavuz, and sold to the fashion industry. Many animal activist groups strongly condemn this barbaric culling. The seal is a protected species in South Africa; there are now only a million seals in the wild. The quota set by the Namibian government for culling the pups, until 2019, will be a million pups.
- Peter Saundry and C.Michael Hogan (2010) South African Fur Seal, Encyclopedia of Earth, National Council for Science and the Environment, Washington DC
- Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham and James A. Powell (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.
- Animal Diversity Web - Arctocephalus pusillus
- Anti-Predatory Strategies of Brown Fur Seals at Seal Island