The beluga whale has skin 10-100x thicker than other animals, and 50% of its body weight is made up of blubber in order to keep it warm in the freezing waters of the Arctic.
A thick insulating layer of blubber is one of the beluga whale’s greatest adaptations to life in the Arctic. It allows the whale to stay warm even when the water is at freezing temperatures. A beluga’s blubber layer is dynamic, varying in thickness seasonally.
Compared to other odontocetes, belugas have an unusually thick layer of blubber, accounting for 40–50% of their body weight. Among other cetaceans, only the right whales have a similar body composition. Thicknesses of up to 27 centimeters, or 10.6 inches, have been reported, but 10 centimeters, or 4 inches, is a more typical maximum thickness.
A beluga’s shape is predominantly the result of its thick blubber layer, which causes a rounded midsection that tapers to a relatively small head and tail. The blubber often results in lumpy sides and undersides, especially in large males. Beluga pectoral flippers are also small in proportion to the whales’ body size.
A beluga’s thick skin also forms a barrier of protection against abrasion by ice in an arctic environment. The temperature of the beluga’s skin is only a degree or two warmer than the surrounding water, but below the skin, the blubber insulates the internal organs and tissues. Belugas have particularly thick skin, 10 times thicker than dolphin skin and 100 times thicker than the skin of terrestrial mammals.
Sources: (AMMPA, 2014, 2017; Balsiger, 2003; Castellini, 2002; Doidge, 1990; O’Corry-Crowe, 2002; Kleinenberg, Yablokov, Bel’kovich, & Tarasevich, 1969; Paine, 1995; Reeves, Stewart, Clapham, & Powell, 2002; Williams, 2002)