Whales

          Whales are the largest animals in world, specially blue whale with his length up to 30m and a weight up to 180 tonnes. But there are many species of baleen whales found in Antarctic waters like the fin, humpback, sei, minke, and the right whale. There are also six species of toothed whales: Sperm, Killer, bottlenose, fourtooth whale and Dolphins.

Baleen of a whale
          The name derive their name from the horny substance, called baleen, contained in plates on either side of the whale’s mouth. The plates are fringed with fine hairs, which form a huge sieve for straining krill and other sea creatures from the water.

          There are two different ways Baleen whales feed. The first, called swallow feeding, they engulf a mouthful of food and water and then squeeze the water our by contracting the grooves in their throat and raising their massive tongues firmly against the roofs of their mouth. The second ways, only practised by the right and sei whale, they’re used to swim with their heads partly out of the water through a swarm of krill. They have their mouths half-open and skim food from the ocean.

          The Baleen whales breed in tropical water in the north. After three months of rich feeding in the south, they migrate back to the temperate waters to give a birth to a single calf, a year after mating. The calves accompany their mothers on the next migration south, living on their mother’s milk. Six month after birth, they are able to feed themselves. Only the calves of the humpbacks and the southern right whales are dependent on their mothers for up to a year.

Blue whale

Blue whale
          Balaenoptera musculus is not only the largest of all whale species, it is also probably the largest animal that has ever lived on Earth. It has on average a weight of 84 tonnes, but there was also a weight of 180 tonnes recorded. Blue Whales are about 24 m long. They occur in all sea around the world but in summer they travel down to the edge of the ice and remain there for most of the southern summer. The northern migration takes place in open ocean and their breeding rounds are still unknown. Blue whales are endangered, shy and rarely seen as they were driven to near extinction by whaling. They were prime targets for whalers by the 1950s has been reduced to an estimated number of 1'000, of the pre-whaling population of 200'000. It may taken a century before there are sufficient numbers to ensure that the species survives.

Fin whale

Fin whale
          Balaenoptera physalus is the second largest of all the whales with a length of 20 m. They grow to an average weight of 40 to 50 tonnes. Females are slightly smaller. Fin whales live and breed in the open oceans, so the don’t travel as far as the blue whales. They feed north of the ice edges almost on krill and similar crustaceans. There are only about 80'000 fin whales remaining but they have been protected since 1976.

Sei whale

          Balaenoptera borealis grow up to 18.5m in length and weigh up to 29 tonnes. They’re closely related to blue and fin whales, but they’re smaller and more slender. Fin whales are oceanic and make long north-south migrations although they only go as far south as 55°S. They have a lifespan of 70 years and it is thought that they may be monogamous. They were hunted after the other whales were protected, but since 1978 they have been also protected in most parts of the Antarctic.

Southern right whale

Southern right whale
          Balaena glacialis australis may reach 18m in length and a maximum weight of 96 tonnes. Its large head makes up to a quarter of its total length and is decorated with callosities, crusty growths on the skin which contain thriving colonies of barnacles, parasitic worms and whale lice. They breed in herds in bays and enclosed waters. They have been hunted until about 1850 because of their large quantities of oil and long baleen plates. Very few remained but their numbers may be recovering today.

Humpback whale

Humpback whale
          Megaptera novaeangliae have an average length of 13 m and weight of 31 tonnes. Their skins are covered with warts and bumps and encrusted with barnacles. Their differ from the other baleen whales in that they are less slender and streamlined than the blue and other rorquals, and they have extraordinarily long flippers, which are up to a third of its total body length. Like their relatives, Humpback whales make north-south migration, but they generally breed in shallow water, often in lagoons among islands. Humpbacks produce the longest and most varied songs in the animal world.

Minke whale

Minke whale
          With an average length of 8 m and weight of 6 to 8 tonnes, Balaenoptera acutorostrata live for about 50 years. They also make north-south migration, but little is known about the paths they take. When in the Antarctic they frequent the ice edge and feed mainly on krill. They were largely ignored by whales until the early 1970s. Since 19775 minkes have been the principal, and since 1979 the only, baleen whale which ca legally be taken in the Antarctic.

          Most toothed whales are much smaller than baleen whales, only the sperm whale matches them in size. There is a great difference between the feeding habits of the toothed and baleen whales. The toothed whales mostly have quite long jaws, often armed with a row of peg-like or cutting teeth. These teeth are well adapted for seizing or cutting up quite large and active prey, and these species feed mainly on fish and squid. The size of its prey varies with the size of the cetacean.

          Toothed whales differ from other mammals in having only one nostril, although two nasal passages are present.

Orca Whale

          Oscines Orca, also called killer whale, reach a length of 9m, while females reach only 8m. The average weight is 7 to 8 tonnes. Killer whales are found in all oceans, from the tropics to the edge of the polar ice. In Antarctic waters orca whale feed on penguins and seals. They eat also fish, but they prefer warm-blooded prey. Packs of killer whales have been seen to attack fin and other whales larger than themselves, tearing mouthfuls of flesh from their living bodies. They are strong enough to toss a fully grown adult sea-lion up into the air. Orca whales live mainly in small packs, which occasionally merge into large herds. The Antarctic population is estimated at about 200 000. In the Antarctic, whalers have shown little interest in killer whales, although about 900 were taken by Russian ships in 1978.

Southern bottlenose Whale

Southern bottlenose whale
          Hyperoodon panifrons is characterised by their cylindrical body that tapers towards the tail. The distinctive "melon" lump on its bulbous head contains oil. There are two closely related species of bottle nose whales, one in the northern and one in the southern hemisphere. The northern species is abundant, but the southern species is rarely seen. The southern bottlenose whale reaches 7 m or more in length and weights 3 to 4 tonnes. They live in quite deep water and can stay submerged for an hour. They feed mainly on squid and cuttlefish. Maybe they migrate north-south, but they’re only found near the polar-ice in summer. Few of the southern bottle nose have been caught by whalers.

Sperm Whale

Spem whale
          Physeter macrocephalus is the only toothed whale which matches the baleen whale in size. Male sperm whale can grow up to 18 m long and weight up to 70 tonnes, while the females grow less than 11.5m long and weight up to 17 tonnes. Only the males reach Antarctic waters.

          The blunt head of the sperm whale, which makes up one third of its body length, contains a wax-filled "case" on top of its skull. The whale can change the density of this spermaceti wax as it dives, thus altering the whole buoyancy of its body.

          They hunt at great depths many species of squid. They reach a speed of 7 to 8 km per hour to depths of 1’000m and below, where they can stay for 45 minutes. In these pitch-black waters they use sonar to locate their luminous prey.

          The sperm whales are well organised. Schools of females and young males live in temperate waters all year and are joined by the males during the summer when mating takes place. Each male has a harem of 20 to 30 females. The calves are born after a gestation period of 15 months and are then suckled for one to two years. But during feeding sperm whales are solitary animals.

          At the end of the 18th and the first half of the 19th century, large herds of sperm whales were hunted in southern waters. After that the demand on whale oil decreased and the whale fishery collapsed. Interest revived in the 1950s and about 5’000 animals a year were caught from 1950 to 67. Declining numbers stopped hunting in 1979.

Southern fourtooth whale

          Berardius arnuxii has an average length of 11m and weight of 8 tonnes. The beaked whales are generally smaller than the bottlenose whales, with a less pronounced forehead. They form large groups, but they’re still difficult to apart them form the bottlenose. Very little is known about them.

Dolphins

Dolphins
          There is no big different of whales and dolphins, the border for the names is only taken from the length, everything smaller than 4 m is called a dolphin. There is only one species, the hourglass dolphin, which is found in the icy waters around Antarctica. Another species, the southern rightwhale dolphin sometimes enters southern waters, but it is essentially a warm water species. The hourglass dolphin (Lagenorhynchus cruciger) is less than two meters long with striking black and white markings. It is not much known about their biology.

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