Seals use blubber for insulation, buoyancy, streamlining and energy.
Under their skin, seals have a thick layer of body fat called blubber. According to the Riverhead Foundation for Marine Research and Preservation, blubber acts primarily as insulation to prevent the loss of body heat in the cold waters that seals inhabit.
Composition
Blubber is composed of lipids (fats), collagen-fiber connective tissues and blood vessels. Blubber covers almost the entire body under the skin and is attached to the animal's muscular system and skeleton through a network of ligaments and tendons.
Other Functions
Blubber is less dense than water or other body tissues and gives the animals' bodies buoyancy. It forms a smooth tissue network under the skin that helps with streamlining as well, making marine mammals such as seals good swimmers. Blubber also stores energy for use by the seal.
Growth and Survival
Adult seals may have up to half their body weight in blubber. Harpseals.org describes how a female harp seal in the Canadian Arctic gives birth to a 24-pound baby that will triple its birth weight in less than two weeks drinking its mother's high-fat milk. Baby harp seals need to develop blubber quickly in order to survive in the cold Arctic environment.
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