Thursday, March 21, 2013

Subantarctic Fur Seal

Arctocephalus tropicalis
The Subantarctic Fur Seal is one of the smaller Fur Seals, and it is also one of the most "tropically" located. They live closer to the Equator than than other Southern Hemisphere relatives do, though they don't quite make it up to the literal tropics... which makes their species name a little misleading.

As with most seals, there is some difference in size between the males and females. Males tend to grow about 2ft longer than the other sex, and can weight three items as much (300lbs vs. around 100lbs). Both sexes do share a similar look, sporting creamy colored faces and chests. However, males are a dark brown over the rest of their bodies, while females are more grey.

Subantarctic Fur Seal
During the breeding season (which begins around September/October), the males haul ashore and stake out territories that they defend. The females eventually follow, choosing a male's territory to reside in. There, she will give birth to her pup that she got pregnant with the previous year, and will with the resident male about a week or two after. Subantarctic Fur Seals have delayed implantation, so though she may have mated in December, the female will not actually be pregnant until April or May. Pups live with their mothers until the next one is born, and though the males may leave after breeding season ends, the mother/pups groups will always stick close to the rookery in order to nurse. Fun fact: the milk that the mothers give to their pups contains 39% fat, which is a lot compared to the 5ish% in human milk!

Subantarctic Fur Seals were in trouble back in the early 19th century-- they were hunted pretty extensively for their pelts. Luckily, the hunted died down and enough Seals remained to allow the population to rebound. There are now around 300,000 individuals, and they are listed as being of Least Concern.

IUCN Status : Least Concern
Location : Southern Indian, Atlantic, and Pacific Oceans
Size : Male body length up to 6.6ft (2m), female up to  4.5ft (1.4m)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Carnivora
Family : Otariidae -- Genus : Arctocephalus -- Species : A. tropicalis

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