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Belugas
(Delphinapterus leucas)
of the
St. Lawrence Estuary

Beluga whales have a very distinctive uniform coloration that changes with age. The male is larger than the female at an average length between 3-5m (10-16ft) but this varies between populations. Their weight is usually between 500 - 1,500 kilos or 5 - 1.5 tons and their lifespan is about 30-35 years although some do live much longer than that.

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 color to Narwhals (Monodon monoceros) but are only found in the company of Beluga adults. Very social and curious studies on belugas in zoological environments indicate that they seek out physical contact with other belugas.

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 colored, has a rough skin which may have creases and folds of fat.

A well-defined crease can be found behind the single blowhole. The blow is visible in the right conditions of light, humidity or temperature. 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.

The Beluga feeds upon squid, fish and crustaceans. Occasionally, they will eat worms and molluscs by dislodging them from the bottom with a jet of water from their mouths. A highly flexible neck aids in the scanning of the sea bottom and the capture of mobile prey. It has a well-defined neck and a prominent rounded melon that resonates during sound production.

The Beluga is one of the most vocal of the toothed whales. It has a large repertoire of clicks, moos, squeaks, trills and twitters that 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.

Beluga have a well-developed, acute sense of hearing and the auditory cortex of the brain is highly developed. They can hear sounds in the range of 1.2 to 120 kHz, with a peak sensitivity of about 10 to 75 kHz. The average hearing range for humans is about .02 to 20 kHz. Most sound reception probably takes place through the lower jaw. A beluga may also receive sound through soft tissue and bone surrounding the ear.

The fat-filled lower jawbone appears to conduct sound waves through the jaw to bones in the middle ears. The lower jaw of toothed whales broadens and is hollow at the base, where it hinges with the skull. Within this very thin, hollow bone is a fat deposit that extends back toward the auditory bulla (earbone complex). Sounds are received and conducted through the lower jaw to the middle ear, inner ear, and then to hearing centers in the brain via the auditory nerve.

A beluga has small external ear openings, a few inches behind each eye. Each opening leads to a reduced ear canal and an eardrum. Some scientists believe that beluga whales receive sounds through these openings. Others believe that a beluga whale's external ear openings are nonfunctional. Biologists have noted sensory areas in beluga whale mouths that may function in taste. Olfactory lobes of the brain and olfactory nerves are absent in all toothed whales, suggesting that they have no sense of smell.

Beluga whales have acute vision both in and out of the water. A beluga's eye is particularly adapted for seeing in water. In air, certain features of the lens and cornea correct for nearsightedness. Their retinas contain both rod and cone cells, indicating that they may have the ability to see in both dim and bright light. (Rod cells respond to lower light levels than cone cells do.) The presence of cone cells suggests that belugas may be able to discern colors. Glands at the inner corners of the eye sockets secrete an oily, jellylike mucus that lubricates the eyes and washes away debris. This tear like film may also protect the eyes from microorganisms and infection.

The Beluga is a slow swimmer, spending much of its time near the surface. It is well adapted to living close to shorelines, it can swim well in very shallow water and move around in depths barely covering its body. If stranded in the shallows it can often survive until the next high tide.

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 resident population of the St. Lawrence River Estuary, Canada. The waters being cold enough year round and rich in food, the St. Lawrence belugas are likely a population that remained in the area since the last glaciation.

The total world population 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 is what has reduced their numbers.

At the beginning of the last century, the St. Lawrence River population was perhaps over 5000 thousand individuals. The population was decimated by hunting and threatened by pollution but with the continuing effort of researchers like Robert Michaud and his team, naturalists and government agencies, these belugas are protected and remain on the endangered list since 1983 when their numbers were estimated to have dropped to about 500. A 1997 aerial survey estimated there were over 600 individuals, today the estimate is that are perhaps as many as 1000 in the entire region.