Southern Elephant Seal

taxobox
name = Southern Elephant Seal
status = LR/lc
status_system = IUCN2.3


regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Carnivora
subordo = Pinnipedia
familia = Phocidae
genus = "Mirounga"
species = "M. leonina"
binomial = "Mirounga leonina"
binomial_authority = Linnaeus, 1758

The Southern Elephant Seal ("Mirounga leonina") is one of two species of elephant seal. It is not only the most massive pinniped but also the largest member of the order Carnivora to ever live. The seal gets its name from its great size and the large proboscis of the adult males, which is used in making extraordinarily loud roaring noises, especially during the mating season.

Size

There is a great sexual dimorphism in size, with the males being much larger than the females. While the females average about 680 kg (1,500 lb) and 3 m (10 ft) long, the bulls grow to around 3600 kg (8,000 lb) and 6.30 m (21 ft) long [] . The record bull, shot in Possession Bay, South Georgia in 1913, was 5,000 kg (11,000 lb) and 6.9 m (22.5 ft) long.

Range and habitat

Southern Elephant Seals are primarily found in Antarctica and other sub-Anarctic islands near the Arctic Polar Front. South Georgia is home to the largest of these populations this one being more than half the entire species population. Other significant populations are found at Macquarie Island, Heard Island, and the Kerguelen Islands. Some births have been reported in New Zealand, Australia, and South Africa. Wandering individuals have been seen as far north as the equator. These seals were heavily exploited during the 19th and early 20th centuries by sealers after their oil. Their numbers have since recovered and now it is not uncommon for them to be seen in Southern Oceanic regions. The population size of Southern Elephant Seals is estimated to be at roughly 600,000 individuals.

Reproduction

Southern elephant seals breed from August to November. The bulls arrive many weeks before the females do and claim territories through loud roars, body positions, and combat fighting. Like its cousin, the Northern elephant seal, this species is highly polygynous and the most successful (alpha) males can have a harem of up to 60 females. Beta males are also present and have smaller harems. The least successful males have no harems but will go as far as to try to seduce an alpha or beta male's females when the male is not looking. An elephant seal must stay in his territory to defend it, which could mean months without eating and having to live on its blubber storage.

Pups are born 0-10 days after the females come to shore and are nursed for up to 23 days. After that the pups are left to fend for themselves while the females mate with the harem males to produce a new pup. The weaned pup may leave the beach and teach itself how to feed. Overcrowded beaches are dangerous for pups as they are often crushed to death.

Food, foraging and predation

Elephant seals feed in deep water, and can dive to great depths - up to 1,700 metres (5,577 ft). Dives lasting up to two hours have been recorded. They feed on cephalopods such as squid and cuttlefish, and on large fish including small, deep-water sharks. When at sea, they spend a high proportion of their time underwater, and they only need to spend a few minutes on the surface between dives. The elephant seal's only significant predator is the orca.

Conservation

After their near extinction due to hunting in the 19th century, total population is about 600,000, but all the populations seem to be declining at present. The reasons for this are unclear, but it may simply be that once protection from hunting was established, the species recovered so fast that it overshot its equilibrium numbers. Most of their most important breeding sites are now protected by international treaty, as UNESCO World Heritage Sites, or by national legislation.

One of the most famous southern elephant seals is Minazo, who lived in Japan's Enoshima Aquarium from when he was a half-year old until his death in 2005. [Minazo album press release (Important Records 2006) [http://search.japantimes.co.jp/cgi-bin/nn20051007b4.html] ] Minazo became popular for his signature bucket-holding, tongue-lolling pose. In 2006, Minazo was memorialized by the Japanese noise musician Masami Akita, AKA Merzbow, in a two volume album (vol. 1, vol. 2) with artwork by Jenny Akita showing Minazo holding his beloved bucket. In 2007, Minazo became the subject of an image macro similar to lolcat called "lolrus". In his liner notes, Masami Akita suggests that Minazo's frequent and demanding performances left him exhausted, contributing ultimately to his death. Akita's intention in celebrating Minazo was to highlight the plight of captive animals used for performance before public audiences. ["Popular Enoshima aquarium seal dies after 10 1/2-year run" (Japan Times 2005-10-05) [http://search.japantimes.co.jp/cgi-bin/nn20051007b4.html] ]

See also

* Northern Elephant Seal

Notes

References

*
* [http://www.antarcticconnection.com/antarctic/wildlife/SEALS/s_elephant.shtml Antarctic Connection - Southern Elephant Seals]
* [http://marinebio.org/species.asp?id=296 MarineBio.org - "Mirounga leonina", Southern Elephant Seal]
*
* [http://animaldiversity.ummz.umich.edu/site/accounts/information/Mirounga_leonina.html Animal Diversity Web - "Mirounga leonina] "

External links

* ARKive - [http://www.arkive.org/species/GES/mammals/Mirounga_leonina/ images and movies of the southern elephant seal]
* [http://www.pinnipeds.org/species/selephnt.htm Southern Elephant Seal]
* [http://www.eleseal.it/ Elephant Seal Research Group]