Southern Elephant Seal (Mirounga leonina) - Wiki
Southern Elephant Seal
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[Photo] ??l??phant de mer du sud, m??le (southern elephant-seal, male). scan de photo :B.navez - Kerguelen - 1999
The Southern Elephant Seal (Mirounga leonina) is one of two species of elephant seal (the other is the Northern Elephant Seal). It is not only the most massive pinniped but the largest member of the order Carnivora as well.
The Elephant Seals get their name from their great size and the fact that the adult males have a large proboscis, which is used in making extraordinarily loud roaring noises, especially during the mating season. There is a great sexual dimorphism in size, with the males very much bigger than the females. While the females average about 680 kg (1,500 lb) and 3 m (10 feet) long, the bulls average around 2200 kg (4,850 lb) and 4.2 m (14 feet) long. The record bull, shot in Possession Bay, South Georgia in 1913, was 5000 kg (11,000 lb) and 6.9 m (22.5 feet) long.
Range and Habitat
Southern Elephant Seals are found throughout the Sub-Antarctic regions. They used to live in large numbers around Tasmania, but were wiped out by the sealing industry and are now only seen there a few times a year. They are occasionally seen off the coasts of New Zealand and South Africa. They breed on the Sub-Antarctic islands, with the population at South Georgia being the largest (it includes about half of the entire species population). Other important populations are at Macquarie Island (over 80,000 individuals), Pen??nsula Vald??s, Heard Island and the Kerguelen Islands.
Southern elephant seals breed from August to November. The bulls arrive many weeks before the females do and claim territories though loud roars, body positions, and combat fighting. Like its cousin, this seal is highly polygynous and the most successful males, the 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 up to 23 days. After that the pups left out to fend for themselves while the female 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 1700 metres. 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 only significant predators on elephant seals are the orca and great white shark .
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.
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