The beluga is also called the white whale because of its milky white skin, and is the only whale species that is completely white. It is gray when born, this color fading gradually with age. It is small in size and lacks a dorsal fin. Beluga are toothed whales, with flexible lips that can produce a range of facial expressions. They have wide, paddle-like flippers and notches in their tails. Their necks are extremely flexible and they can turn their heads almost 90 degrees sideways. Their extremely thick layer of blubber provides insulation in freezing Arctic waters. Their bodies are fifty percent fat, much higher than other non-Arctic whales, with body fat of only twenty percent.
Beluga whales occur in the Arctic and sub-Arctic waters of the Arctic Ocean’s coastal areas, as well as the adjoining seas, preferring inlets, fjords, bays, channels, and the shallow Arctic waters warmed by continuous sunlight. Sometimes in the summer they are found at river mouths.
The beluga whale is a diurnal and very social animal. During summer, thousands of them gather together in river estuaries to moult. They rub their bodies on the gravel of the sea bed to shed their yellow, withered skin from the previous year and to again become gleaming white. At this time, females with babies will often group together, while males gather in large bachelor groups. Belugas are able to dive deeper than 1,000 m, but usually they are found up on the surface, swimming slowly. During winter it may become necessary to form breathing holes amongst the ice, which they do with their heavy heads. Most populations of these whales migrate north in spring, then south in autumn once ice begins to form.
Belugas eat a variety of prey, such as smelt, flatfish, flounder, salmon, sculpins, and cod. They also eat invertebrates such as crabs, clams, shrimps, worms, octopus, squid, and more creatures that live on the seabed.
Beluga whales are polygynous, a dominant male often mating with several females during one mating season. They tend to mate between late February and early April. Gestation lasts 14 months and a single calf is produced. The calf has a grayish color and is very well developed. The nursery pod stays together during the delivery, then all of them move off except for a teenage nursemaid. Birthing usually takes place near rivers because the temperature of the water is ten degrees higher there. This is for the benefit of the calf, which has less blubber than a full-grown adult. The newborn stays between the two females, their swimming pulling him along with the current. A calf totally depends on its mother’s milk for one year, and lactation lasts as long as 1.5 to 2 years. Females are sexually mature in 4 to 7 years, and males in 7 to 9 years.
Hunting by Inuit and Alaska Native groups is the biggest known threat to belugas across certain portions of their range. Further threats are contamination of river estuaries, infectious diseases and disturbance by vessel transport, gas and oil production. An increasing concern is noise, which can damage a whale’s hearing and affect its ability to navigate, communicate, and locate prey.
According to the IUCN Red List, the total size of the beluga whale population is above 150,000 animals. There are estimates for this species’ populations in specific regions: In Alaska: Cook Inlet – 375 whales; Bristol Bay – 1,642- 2,133 whales; Eastern Bering Sea - 18,142 whales; Eastern Chukchi Sea - 3,710 whales; Eastern Beaufort Sea/Beaufort Sea (shared between Alaska and Canada) - 39,258 animals. In Canada: Cumberland Sound - 1,500 whales; Ungava Bay – fewer than 50 whales; West Hudson Bay - 23,000 whales; southern Hudson Bay - 1,300 whales; East Hudson Bay – 3,100 whales; St Lawrence River - 900–1,000 whales; Eastern High Arctic/Baffin Bay - 21,213 whales. Shared between Canada and Greenland: West Greenland - 7,941 whales. Russia: Eastern and Central Russian Arctic - 18,000–20,000 whales; Western Russian Arctic - 1,000 whales. Beluga whales are classified as a near threatened (NT) species currently.