Taxonomy & Nomenclature
Physical Description / Field Identification
The white whale, or beluga, is a robust animal. Its basic body shape is much like that of the narwhal; it has a small bulbous head with only a very short beak, no dorsal fin (instead, a shallow transversely-nicked ridge runs along the midline of the back), small rounded flippers (with curled tips in adult males), and flukes that often have a convex trailing edge. Belugas are "blubbery;" their bodies are supple and often wrinkled. There is often a visible neck, which is unusual for cetaceans. Because the cervical (neck) vertebrae are not fused, white whales can move their heads more than most other cetaceans.
At birth, white whales are a creamy pale gray, and they rapidly turn dark gray to brownish gray. They whiten increasingly as they age, reaching the pure white stage between five and twelve years of age. The mouth generally contains nine, often heavily worn, teeth in each row of the upper jaw, and eight in each row of the lower jaw.
Most white whales are less than 5.5 m (males) or 4.1 m (females), and large animals may weigh up to 1600 kg. Calves average about 1.6 m at birth.
Can be Confused With
Belugas can be confused with narwhals, which overlap in much of their range. The black and white spotting/blotching of narwhals, and the tusks of males of this species, should permit accurate identification in most situations.
Distribution
White whales are panarctic, found only in high latitudes of the Northern Hemisphere. They are widely distributed throughout the arctic and subarctic regions, from the west coast of Greenland west to eastern Scandanavia and Svalbard. They occur seasonally (mainly in summer) in shallow coastal waters; however, they often move into deep, offshore waters in other seasons. Belugas enter estuaries, and even rivers; there are a few records of solitary individuals ranging thousands of kilometers up various rivers. At least 15 stocks of white whales have been recognized, based on morphological, genetic, and distribution differences.
Ecology and Behavior
The highly gregarious beluga is most often found in groups up to about 15 individuals, but it is sometimes seen in aggregations of thousands. Pods are often segregated by age and sex; all-male groups and mixed aggregations, including females and young, are known.
In general, white whales are not showy at the surface and they do not often leap. These animals generally swim slowly. During the summer, they aggregate in large numbers in shallow estuaries, and at these times can be very active. Their extreme loquaciousness has earned them the name "sea canary."
Calves are born in spring to summer, between April and September, depending on the population.
Feeding and Prey
Although various species of fish are considered to be the primary prey items, white whales also feed on a wide variety of mollusks and benthic invertebrates. Based on stomach contents, belugas are thought to feed mostly on or near the bottom.
Threats and Status
Belugas have been hunted commercially in the past, and exploitation by native Arctic peoples continues today in a number of areas. Some stocks have been badly depleted, if not extirpated, by past hunting. Their predictable migation patterns and habit of aggregating in shallow water makes them relatively easy to kill.
Incidental captures in gillnets and other fisheries cause some mortality, and several hundred have been captured for captive display and research. In addition, habitat degradation, behavioral disturbance (mainly by oil and gas exploration and extraction activities, as well by hunters and fishermen), and pollution may be causing further problems for these animals. The population in the St. Lawrence River is apparently recovering slowly from past exploitation, most probably due to the damaging effects of organochlorines on the animals’ health and reproduction.
Currently, belugas are ‘Vulnerable’ (IUCN) and ‘Not Listed’ (ESA).
Links
References
Born, E.W., R. Dietz and R.R. Reeves (eds). 1994. Studies of white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) in Greenland and adjacent waters. Meddelelser om Gronland Bioscience 39:1-259.
Lesage, V. and M.C.S. Kingsley. 1998. Updated status of the St. Lawrence River population of the beluga, Delphinapterus leucas. Canadian Field-Naturalist 112:98-114.
O’Corry-Crowe, G.M. 2002. Beluga whale (Delphinapterus leucas). pp. 94-99 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Reeves, R.R. and D.J. St. Aubin (eds). 2001. Belugas and narwhals: Application of new technology to whale science in the Arctic. Arctic 54(3):207-355 (Special Issue).
Stewart, B.E. and R.E.A. Stewart. 1989. Delphinapterus leucas. Mammalian Species 336:1-8.
