Beluga Whale

Beluga Whale

(Delphinapterus leucas)

The Beluga whale has a very distinctive uniforn light colouration which changes with age. The male is larger than the female at a length of 3-5m (10-16ft) but this varies between populations. A Belugas weight is between 500-1,500kg. It is a slow swimmer and spends much of its time near the surface. They are prone to becoming trapped in ice making them easy prey for hunters and Polar bears. Body scars caused by unsuccessful bear attacks are fairly common in some pods.
The adult Beluga is white but may appear yellowish at certain times of the year. The young are slate-grey to reddish-brown which changes to blue-grey at 2 years of age. Young animals may be similar in colour to Narwhals (Monodon monoceros) but are only found in the company of Beluga adults. The Beluga has a stout body with a small head and a short but distinct beak. Teeth are arranged in both the upper and lower jaws, 8-11 pairs of irregular often curved teeth in the upper jaw and 8-9 pairs in the lower jaw. It has a well-defined neck and a prominent rounded melon which may resonate during sound production.
Like the Narwhal the Beluga has no dorsal fin. Instead, a Dorsal ridge extends along the back for about 50cm (20in) and may form a series of dark bumps. Both have unusually shaped flukes with convex trailing edges. They seem to face backwards in the Narwhal and although not as pronounced in the Beluga the trailing edges do become more convex with age. Flippers are broad, short, paddle-shaped and highly mobile. Much of the Beluga body, although evenly coloured, has a rough skin which may have creases and folds of fat. A well-defined crease can be found behind the single blowhole.
The Beluga is one of the most vocal of the toothed whales. It has a large repertoire of clicks, moos, squeaks, trills and twitters which can be heard above and below the surface. By altering the shape of its forehead and lips a Beluga can make a variety of facial expressions. It may appear to smile, frown or whistle and while this may be a form of communication it is related to sound production. It may also have the most versatile and sophisticated sonar system of any cetacean. The Beluga is well adapted to living close to shore, it can swim in very shallow water and manoeuvre in depths barely covering its body. If stranded it can often survive until the next high tide.
The Beluga feeds upon squid, fish and crustaceans. Occasionally, they will eat worms and molluscs by dislodging them from the bottom with the emission of a jet of water. A highly flexible neck aids in the scanning of the sea bottom and the capture of mobile prey.
Family: Monodontidae
Subfamily: Delphinapterinae
Other Names: Belukha, Sea Canary, White whale
Belugas are circumpolar, mainly Arctic but extending to subarctic, occupying coastal and estuarine areas. They are found off the coasts of Scandinavia, Greenland, Svalbard, the former Soviet Union, and North America. Many Belugas winter in areas of loose pack-ice where wind and ocean currents keep cracks and breathing holes open. Summers are spent in shallow bays and estuaries while some populations swim 1,000km (620miles) or more up river.
Most populations do not make extensive migrations. The longest migration is by those that winter in the Bering Sea and summer in the Mackenzie River, Canada. Some make no migration at all, such as the residents of the St. Lawrence River, Canada.
The total world population is unknown but is probably between 40,000 and 55,000. Most reside in Baffin Bay, Davis Strait, the Barents, Kara and Laptev Seas.
The Beluga has been hunted by Arctic native people for hundreds of years but over-hunting by commercial operators during the 20th century has reduced their numbers. Present hunting rates are predicted to cause further population declines in Eastern Canada, Barents and White Seas.

Bibliography

Whales on the Net

 
 
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