Beluga whale (Delphinapterus leucas) COSEWIC assessment and status report: chapter 5

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Species Information

• Name and Classification
• Description

Name and Classification

The beluga whale, Delphinapterus leucas (Pallas, 1776), derives its name from the Russian belukha, which means white. In English, it is also called the white whale; in French béluga is the current common name although marsouin blanc or baleine blanche were previously used; in the various Inuit dialects they are called qilalugaq (Inuktitutt, Inuinactun, Inuvialuktun) and siqsuaq by the Inupiat of the Alaskan north slope.

The beluga belongs to one of two monotypic genera of the family Monodontidae (Rice 1998), which includes the narwhal, Monodon monoceros, as the other member. These two species as well as the Arctic bowhead whale, Balaena mysticetus, lack dorsal fins, a common characteristic thought to be an adaptation to life in ice-filled Arctic waters.

Description

Adult belugas are distinct in being pure white and can weigh up to 1900 kg (Fig. 1). They range in total length from 2.6 to 4.5 meters, adult females are approximately 80% of the adult male length (DegerbØl and Nielsen 1930, Vladykov 1944, Brodie 1989, Doidge 1990).

Figure 1: Line Drawing of Beluga Whale, Delphinapterus leucas

By D. Codère, E.M.C. Eco Marine Corporation.

Newborn calves are grey at birth, sometimes with a darker mottled coloration, and 150 cm in length, which is 48% of the length of their mothers. Yearling calves are 60-65% of their mothers’ length (Caron and Smith 1990). Older juvenÎles gradually become paler in colour until they turn pure white at, or shortly after, the age of sexual maturity (Sergeant 1973, Heide-Jørgensen and Teilmann 1994).

Belugas are easily sighted in calm water because of their white coloration. During the spring migrations along the ice edges, or in leads, they may be seen in aggregations of several hundred animals in certain parts of the Arctic (Lønø 1961, Sergeant and Brodie 1975). Belugas are the only Arctic cetacean species that commonly frequent river estuaries, sometimes numbering thousands of individuals, where they may predictably be seen shortly after the break-up of the sea ice. There they rub on the bottom of the shallow river channels and frequent the warmer fresh-water for several weeks (Fraker et al. 1979, Smith and Martin 1994).