The Beluga belongs to the monodontidae family and typically has no dorsal fin. Like all whales, its skin is hairless with a fairly thick top layer. This is some 5-12 cm thick in the case of the white whale. The subcutaneous tissue is made up of a fat layer which, depending on nutrition, sex, and age, is 2-22 cm thick. The white whale gets its name from its colours, which changes during the course of its life. Newborn belugas are slate grey to brown coloured and after about a year take on a blue-grey colours which they retain until they are about five. During this time, they are referred to as ‘blues'. then the animals turn all white, although a bluish shimmer can remain, especially in females. Since belugas often frequent the edges of pack ice, their white colouring likely provides camouflage protection against Polar bear attacks.