Brown Fur Seal
name = Brown Fur Seal
status = LR/lc
status_system = iucn2.3
phylum = Chordata
genus = "
species = "A. pusillus"
binomial = "Arctocephalus pusillus"
binomial_authority = (Schreber,
range_map_caption = Distribution of the Brown Fur Seal, dark blue: breeding colonies; light blue: non-breeding individuals
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
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.
The structure of the brown fur seals flipper is homologous to that of many other animals such as the structure of a bat’s wing or the arm of a human. This is because the seal’s flipper consists of the same basic bone structure as the previously listed examples. As you can see in the linked diagrams below the seals flipper is made up of a series of bones which are exactly the same as that of a bat or human. They have a humerus, which is connected to two forearm bones, the ulna and radius, which then meet a series of smaller wrist bones known as the metacarpals, which connect to the phalanges better known as fingers. This suggests that all of these animals have evolved from a common ancestor at some stage and have developed the structure of their unique limbs to suit their needs best. [http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_mammals/Phocidae/v12_id99_con_rearflip.jpg/view.html] [http://itc.gsw.edu/faculty/bcarter/histgeol/paleo2/limbs.jpg] .
The Brown Fur Seals flippers are analogous to the flippers of animals such as the right whale and the blue whale because they have all independently developed the flipper which has a similar function even though they are not closely related to each other.
This mammal phylogenetic tree, on the link below, shows that the brown fur seal, who are in the family otariidae, are closely related to the walrus who are in the Odobenidae family. The seal and walrus diverged from a common ancestor approximately 30 million years ago. If you go back as far as 80 million years ago the brown fur seal even has a common ancestor with certain types of bats and horses. [http://gregladen.com/wordpress/wp-content/graphics/mammal_tree_lg.jpg]
Distribution and habitat
The Brown Fur Seal is found along the coast of
Namibiaand along the west coast of South Africato the Cape of Good Hopeand the Cape Province. Its Australian subspecies breeds on nine islands in the Bass Straitbetween Tasmaniaand Victoria.
Both subspecies mostly haul out and breed on rocky islands, rock ledges or reefs and pebble or boulder beaches. However South African Fur Seals have large breeding sites on sandy beaches in South Africa, and a non-breeding 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 shelfwhile the African subspecies forages in the open ocean.
Behavior and reproduction
Although Brown Fur Seals normally travel alone, large group of these seals can be seen rafting in
kelpbeds. Pregnant females will stay 7 weeks away from the land before the breeding season.
Brown Fur Seals breed in mid-October. Unlike many eared seal species, females are free to choose their 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. In False Bay, the seals employ a number of anti-predatory strategies while in shark-infested waters such as:
*Swimming in large groups
*Low porpoising; to increase sub-surface vigilance
*Darting in different directions to cause confusion when attacked.
*It rides near the dorsal fin to keep out of reach of the shark's jaws when attacked.
The Brown Fur Seal is an inquisitive and friendly animal when in the
waterand 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 landthey are far less relaxed and tend to panic when people come near them. Australianfur seals were hunted greatly 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. However the Tasmanian government authorized the killing of "nuisance" fur seals in October 2000.
South African fur seals have a very robust and healthy population despite annual harvesting.
* [http://animaldiversity.ummz.umich.edu/site/accounts/information/Arctocephalus_pusillus.html Animal Diversity Web - "Arctocephalus pusillus"]
* [http://www.elasmo-research.org/education/white_shark/seal_antipred.htm Anti-Predatory Strategies of Brown Fur Seals at Seal Island]
* [http://blog.lukaesenko.com/2008/07/17/cape-cross-seal-colony/ Photos of Brown Fur Seals at Cape Cross, Namibia] — Photographs and information.
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Look at other dictionaries:
fur seal — any of several eared seals, as Callorhinus alascanus, having a plush underfur used in making coats, trimmings, etc. [1765 75] * * * Any of nine species of eared seals valued for their fur, especially the chestnut coloured underfur. Fur seals live … Universalium
Northern fur seal — Animalia Northern fur seal Northern fur seal bull, St Paul Island, 1992 Conservation status … Wikipedia
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Antarctic Fur Seal — Taxobox name = Antarctic Fur Seal status = LR/lc status system = iucn2.3 regnum = Animalia phylum = Chordata classis = Mammalia ordo = Carnivora subordo = Pinnipedia familia = Otariidae subfamilia = Arctocephalinae genus = Arctocephalus species … Wikipedia
Northern Fur Seal — Taxobox name = Northern Fur Seal status = VU trend = unknown status system = iucn2.3 image width = 300px image caption = Northern Fur Seal Bull, St Paul Island, 1992 photo by Rolf Ream, NMML. regnum = Animalia phylum = Chordata classis = Mammalia … Wikipedia
Galapagos Fur Seal — Taxobox name = Galapagos Fur Seal status = VU trend = unknown status system = iucn2.3 image width = 200px regnum = Animalia phylum = Chordata classis = Mammalia ordo = Carnivora subordo = Pinnipedia familia = Otariidae subfamilia =… … Wikipedia
Guadalupe Fur Seal — Taxobox name = Guadalupe Fur Seal status = VU trend = unknown status system = iucn2.3 image width = 240px regnum = Animalia phylum = Chordata classis = Mammalia ordo = Carnivora subordo = Pinnipedia familia = Otariidae subfamilia =… … Wikipedia
Subantarctic Fur Seal — Taxobox status = LR/lc status system = iucn2.3 regnum = Animalia phylum = Chordata classis = Mammalia ordo = Carnivora subordo = Pinnipedia familia = Otariidae subfamilia = Arctocephalinae genus = Arctocephalus species = A. tropicalis binomial =… … Wikipedia
South American Fur Seal — Taxobox name = South American Fur Seal status = LR/lc status system = iucn2.3 image width = 250px image caption = South American fur seals at Bristol Zoo Gardens, England regnum = Animalia phylum = Chordata classis = Mammalia ordo = Carnivora… … Wikipedia
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