Making Energy from Blubber
Elephant seals have a thick layer of blubber that keeps them warm in the deep, cold sea. Blubber is fatty tissue found under the skin in all pinnipeds.
Blubber is different from other types of fat, however, in that it is laced with blood vessels and collagen fibers. It functions as an insulating layer, keeping internal organs warm in an ocean environment below 40° F (4.5° C) and also keeps the seal buoyant and streamlined for efficient passage through water. In addition, elephant seals are able to metabolize their blubber, burning the fat for energy when they are fasting. Water is a by-product of blubber metabolism which allows them to survive extended periods of fasting.
Blubber may account for nearly 50% of an adult male’s weight at the beginning of the pupping and breeding season (December). By the end of breeding season in March, adult elephant seals of both sexes will have lost about 40% of their weight through blubber metabolism.