Seals are Antarctica's only indigenous land mammals. 6 species are to be found in these areas:
- Antarctic Peninsula and the South Shetlands: Antarctic Fur Seal, Southern Sea Lion, Leopard Seal, Crabeater Seal, Southern Elephant Seal
- Falkland Islands: South American Fur Seal, Southern Sea Lion, Leopard Seal, Southern Elephant Seal.
- South Georgia: Antarctic Fur Seal, Leopard Seal, Southern Elephant Seal
- Southern Chile and Southern Argentina: South American Fur Seal, Leopard Seal, Southern Elephant Seal.
They belong to two distinct families: eared seals (sea lions and fur seals) and earless or true seals (elephant, leopard, crabeater and Weddell seals).
Southern Elephant Seal
Breeding male elephant seals are colossally splendid.
They are massive, bloated, lumbering giants, six times heavier than their many wives, and sporting a grotesque proboscis. Ill-tempered, belligerent, given to much roaring and belching, their chief pre-occupation is establishing as large a harem as possible - and woe-betide any other male with similar intentions who might fancy his chances. Fights are commonplace, with rival bulls roaring at each other at close range, elaborately inflating their proboscises and lunging at the other's neck. If they get beyond the initial posturing blood will be spilt, as the scars on aged males will testify.
All that testosterone can result in harems of up to 100 females, though a respectable figure is 30. The flip side is that bulls have to wait until they are at least ten years old before they stand a chance of sexual success, and 90% of them will never mate at all.
Leopard seals are the consummate hunters of the Antarctic, living all around the continent's coast. They are seen along the Antarctic Peninsula, on the South Shetlands and South Orkneys, occasionally on South Georgia, and even sometimes on the Falklands and the southernmost coasts of Argentina and Chile.
Long, sleek, graceful, muscular and fast, with large heads and impressively powerful jaws, leopard seals are famed for their predation of penguins and seal pups, mostly taken in the water where their power and agility makes easy work. The current record stands at 250 penguins per seal every week for 15 weeks. That's a lot of penguins.
But penguins and young seals are not always in plentiful supply, so the leopard seal's main diet is the ever-present fish, squid and krill. Like crabeater seals their teeth are specially shaped for filtering krill - as well as tough enough and sharp enough for their larger prey.
Ashore, leopard seals prefer ice not land. Largely solitary, they rest on pack ice or ice floes, where they laze about sleeping or smiling a winsome slightly sinister grin as they pose for the cameras on a passing zodiac. To some people their long sinuous bodies seem snake-like, with a facial expression to match. With a quick flip they launch themselves into the water whenever hunger calls.
In the water they are especially agile and very fast, reaching speeds of 25mph. Getting back on to the ice is not a problem: they can project themselves straight out of the sea at an exit speed of 20 feet per second to reach shelves of ice up to 2 metres above the water line. Not bad for an animal up to 3.8m long weighing half a tonne. Their coat is more-or-less spotted, which accounts for their name.
Because leopard seals live on the ice and most of their activity is carried out at high velocity under the waves, not a lot is known about the detail of their lives. In December and January they become extremely vocal, especially underwater, which is where partnerships are consummated. Single pups are born on the ice 11 months later, in late October and November, and kept safe and snug in snow holes tended by their mums for a very brief period of about 4 weeks until they are quickly weaned and ready to explore the world beneath the waves and the ice for themselves.
Although there are some reports of leopard seals being taken by orcas, adults are generally secure at the top of the food chain to live long lives of up to 30 years.
Leopard seals generally leave humans alone. But there are very very occasional reports of a seal mistaking a human walking by the edge of the ice for a large tasty penguin. The seal shoots out of the water with evil intent but realises its mistake before any contact is made, both parties registering considerable surprise. A wildlife photographer diving with leopard seals was befriended, played with and brought food, but don't try this yourself - another diver was attacked and dragged into the deep.
Current estimates of leopard seal numbers are around 200-250,000.
Southern Sea Lion
The only sea lions in this area, Southern (or 'South American') sea lions range from Peru and south-east Brazil down to Tierra del Fuego and the Falklands. They are not found in the more southerly islands or Antarctica.
Heavily built, large seals with noticeable but tiny ears, sea lion males grow to around 2.8m and a muscular 500kg: females are smaller and a lot slimmer.
Antarctic Fur Seals
Antarctic fur seals inhabit South Georgia (their main stronghold), South Shetlands and South Orkneys, and the islands off the Antarctic Peninsula. They are the only 'eared' seal in this range, and like all eared seals they can also stand on all four flippers. They can get about quite well on land, reaching an inelegant gallop that can easily outpace human visitors: keep your distance.
November to mid-January is the breeding season for fur seals, when males establish their territories. Females come to settle under the protection of the most vigorous males, granting mating rights in return, so males aggressively defend their territories against other males 24/7 for two months - with few opportunities to eat over the whole period of their dominance. The largest and most spectacular breeding grounds are on South Georgia, where most fur seals migrate for the season.
They are keen to keep humans out of their territories too, so guides on shore visits near fur seal colonies will be especially keen to respect their boundaries at this time.
Their cousins, the South American fur seal, are found around the coast of South America and the Falklands, and as far north as the Galapagos Islands.
Crabeater seals are the most numerous seals in the Antarctic, with 15 million or so individuals.
They are scattered all around the Antarctic coast, mostly in small groups, and are a common sight on pack ice along the Antarctic Peninsula and around the South Shetlands. A few reach South Georgia or the Falklands, so although they are one of the most numerous seals in the world, very few people - only those who have visited the Antarctic - have ever seen them.
Crabeaters are relatively slim, quite lithe and highly adapted to feeding on krill, and lots of it. Their teeth are specially designed to strain the water as they swim back and forth, mouths agape, through shoals of krill a few metres below the surface. Much of their feeding is done at night when krill are closest to the top, leaving the daylight hours for rest and play.
Crabeaters are medium-sized for a seal: they reach about 2.4m in length and weigh 225kg with a smooth coat aging from tan through to a pale blonde. Many individuals bear scars from attacks by leopard seals or orcas.
The world's most southern mammal, the large and very plump Weddel seal inhabits the rim of the Antarctic continent where it lives on pack ice and fast ice over the sea - but not out at sea on ice floes. Weddells' most striking behaviour is to maintain a hole in the ice sheet to dive for fish and return to breath between dives.
Weddell seals can be seen along the Antarctic peninsula, the South Shetlands, South Orkneys and South Georgia, with few vagrants any further afield than this. The total population is hard to estimate but thought to be around 800,000. Adult size is 2.5-3.5m weighing 400-600kg, with a smooth greyish strongly patterned or mottled coat, small round head and very rotund body.
Most dives are short - just a few minutes - but Weddells are consummate divers and can hunt underwater for up an hour before needing to breathe. They can dive repeatedly before eventually hauling out on to the ice to rest and recover.
Once under the ice, Weddells mainly hunt fish, with some squid and crustaceans. They have keen eyesight, swim quickly, and must have good navigational skills to return to their small breathing holes. The seals have extra sharp teeth to help them chew the ice away around their diving holes to keep them clear - a severe problem in the winter months.
Males establish territories beneath the ice and demand mating rights over any female entering their zone, especially during their November - December courtship months when females are attracted by males' undersea calls. Weddell seals form large colonies in their pupping season from late September to early November to give birth on the ice, with pups able to swim after two weeks and fully weaned at 8 weeks. At other times you will see them scattered in small numbers, but always away from open sea.
As they age their teeth may become so worn that they are unable to maintain their diving hole over the Antarctic winter and cannot survive.