The word beluga comes from the Russian word "bielo" meaning white. However, these white whales are born dark gray. It can take up to eight years before they turn completely white. The white colouration of the skin is an adaptation to life in the Arctic that allows belugas to camouflage themselves in the polar ice caps as protection against their main predators, polar bears and killer whales. Unlike other cetaceans, the belugas seasonally shed their skin.