"Beluga are a Northern Hemisphere species, and have a thick layer of blubber that enables them to live in icy polar waters. They breed in the winter. The mother's pregnancy lasts about a year, and the calf nurses for two years on her rich milk. Beluga visit warm-water estuaries during the summer, possibly because warmth may accelerate the annual molting, or shedding, of their outer skin. After they molt, they are bright white. They are social animals who live in groups called ""pods,"" which may consist of several hundred individuals. Beluga make a variety of squeaks and chirps while traveling. Sailors who could hear them through the sides of their wooden ships called them ""sea canaries."" Polar bears and killer whales are known predators."
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Original description: Pallas, P.S., 1776. Reise durch verschiedene Provinzen des Russischen Reichs, p. 85. St. Petersbourg, viii, Pt. 2, nxxvi.