Seals
There are six species of seal in Antarctica; of which five were seen (the Ross Seal is very rarely seen). The Southern Elephant Seal is the worlds largest seal, males are typically 3.5 tonnes and can be 20ft in length. There distinctive size and pendulous trunk makes them both easy to identify and the origin of their name obvious. In contrast the female is typically less than 1 tonne and 12 ft in length. They spend the winter at sea and are known to dive up to 2km deep and spend up to 2 hours beneath the surface feeding mainly on squid. They come ashore from about late August, when the males fight for dominance over the harems of females, which can be up to 100 strong. Pups are normally born between October and December, they weigh 45 kg at birth but quadruple in weight on their mothers rich 50% fat milk in the 4 weeks before they are weaned. After mating the mature seals moult before heading back to sea.
Fur seals have a similar seasonal cycle and also breed in harems. Despite being significantly smaller, typically males weigh 200 Kg and females about 45 kg, they are very aggressive and territorial.
Both have in the past been hunted to near extinction but populations are now fully recovered and indeed, all be it controversial, there are suggestions that in some areas it may be necessary to cull them.
Typically Weddells live the furthest south (although there is a small breeding colony on South Georgia). The Weddells mate at sea and females typically give birth in small groups on inshore ice flows. Crabeaters are similar to the Weddell and recognition between the two species can be difficult, both grow to about 10 feet long and are much more solitary then Fur or Elephant seals. Despite being the worlds most abundant seal, very little is known about the crabeater, it is believed to breed out in the pack ice in spring but this has never been observed.
The leopard Seal is another solitary species and its awesome gape makes it quite distinctive. Males grow to about 9 feet and weigh 300Kg, females are larger at about 12 feet and 450Kg. Little is known about their breeding habits. The tourist industry has consistently underplayed the dangers of these seals to humans. However a few attacks on people and inflatables are documented and in the 2003-4 season a Leopard seal attacked and killed a BAS scientist. The expedition had only one confirmed encounter with a leopard seal; it was lying on an iceflow as we sailed past, closing to take a look that awesome gape sends a cold shiver down the spine.
Although seals may appear cumbersome and ill adapted when viewed on land, most can move faster than a man over short distances and should be treated with a certain amount of respect, they actually spend most of their lives at sea and are extremely well adapted for their environment. |