The Beluga Whale or White Whale (Delphinapterus leucas), is an Arctic and sub-arctic species of marine mammal. It is commonly referred to simply as the Beluga. The Beluga occurs in waters from 50Â° N to 80Â° N. There is also an isolated population which travels the St. Lawrence River estuary and the Saguenay Fjord. There is an endangered colony of Belugas in the Cook Inlet in Alaska as well.
This small whale can grow up to 16 feet long and is larger than most dolphins, but smaller than most toothed whales. Males are typically larger than the females and can weigh as much as 3,000 pounds. Females weigh closer to 2,000 pounds. Newborn belugas are about 5 feet in length and weigh about 175 pounds. The adult beluga is unique. It is all white and has a dorsal ridge rather than a fin.
The body of the Beluga is rotund, particularly when well-fed, and tapers smoothly to both the head and tail. The tail fin grows and becomes increasingly ornately curved as the animal ages. The flippers are broad and short, making them almost square-shaped. The head is extremely bulbous and soft. The beluga is able to change the shape of its head by blowing air around its sinuses. Again unlike many dolphins and whales, the vertebrae in the neck are not fused together, allowing the animal flexibility to turn its head laterally.
Females become sexually mature at five years, males at eight years. Females give birth to a single calf in the spring after a gestation period of fifteen months on average. The young are uniformly gray in color. The gray steadily lightens until they are all white by the age of 7 to 9 years. Mothers nurse their young for about two years. Females remain sexually active until they are around 20 years old and some live to 50 years or more.
Belugas are slow-swimming mammals which feed mainly on fish. They also eat cephalopods (squid and octopus) and crustaceans (crab and shrimp). Foraging on the seabed typically takes place at depths of up to 1,000 feet, but they can dive at least twice this depth. Generally a feeding dive will last 3-5 minutes, but belugas have been observed submerged for up to 20 minutes at a time.