• Blubber is a thick layer of fat, also called adipose tissue, directly under the skin of all marine mammals. Blubber covers the entire body of animals such as seals, whales, and walruses—except for their fins, flippers, and flukes.
    Blubber an important part of a marine mammal's anatomy. It stores energy, insulates heat, and increases buoyancy.
    Storing Energy
    Energy is stored in the thick, oily layer of blubber. The energy stored in blubber includes both proteins (mostly collagen) and fats (mostly lipids). The ability of blubber to use these stored nutrients means marine mammals are not forced to search for food for long periods of time. Nursing mothers, for instance, build up thick stores of blubber before giving birth. In addition to feeding offspring, mothers cannot regularly search for food. They rely on the energy stored in their blubber.
    Blubber also insulates marine mammals, or helps keep them warm in icy waters. This insulation is necessary. Mammals are warm-blooded, meaning their body temperature stays about the same no matter what the temperature outside is. Keeping a warm body temperature in cold water requires more energy than keeping a warm body temperature in warm water. Some marine mammals, such as sea otters, have a thick fur coat, as well as blubber, to insulate them.
    To insulate the marine mammal, blood vessels in blubber constrict, or get smaller, in cold water. Constricted blood vessels reduce the flow of blood, thus reducing the energy required to heat the body. This conserves heat.
    Finally, blubber helps marine mammals stay buoyant, or float. Blubber is generally less dense than the ocean water surrounding it, so animals naturally float.
    Animals with the thickest blubber, such as right whales, are found in Arctic and Antarctic regions. In these animals, blubber is more than a foot thick! The thickness of their blubber does not indicate better energy storage, insulation, or buoyancy, however. Those characteristics are determined by the chemical property of the blubber.
    People and Blubber
    Many ancient cultures of the Arctic relied on blubber as a staple part of their diet. Muktuk, for example, is a traditional food consumed by the Eskimo and Inuit people, native to the U.S. state of Alaska and the Canadian Arctic. Muktuk is thick slices of whale blubber and skin. Besides being an excellent source of energy and vitamin D, muktuk was often the chief source of vitamin C for these Arctic people. (Citrus trees, whose fruit is probably the most familiar source of vitamin C, do not grow in such cold temperatures.) 
    Today, the process of biomagnification has made consumption of muktuk and other whale meat a possible health risk. Biomagnification is the process in which the concentration of a substance increases as it passes up the food chain. Blubber's high concentration of toxic substances may be a result of marine mammals' position as top predators in the marine food web. High concentrations of PCBs, chemicals that can cause cancer, and other toxins have been detected in blubber. The concentrations may be natural, or it may be augmented by bioaccumulation of marine pollution.
    Some countries, such as Japan and Norway, continue to harvest whale blubber for food. Environmental groups have expressed concern about the high concentration of PCBs in the blubber.
    Blubber was the basis of the whaling industry, one of the most lucrative businesses of the 18th and 19th centuries. Millions of whales were hunted throughout the Atlantic, Pacific, and Arctic oceans in sophisticated whaling "factory ships." 
    After killing a whale and stripping it of its blubber, workers rendered the blubber in enormous iron cauldrons called trypots. Rendering is the process of slowly cooking blubber or other animal fat (such as lard) over a low temperature.
    As blubber renders, it turns into a waxy substance called whale oil. Whale oil was a primary ingredient in soap, margarine, and oil-burning lamps. Today, some indigenous Arctic communities, such as the Inuit, still harvest blubber and render it for use in traditional whale-oil lamps. 
    The whaling industry dwindled as petroleum and natural gas replaced whale oil as a major fuel source. Vegetable oils replaced whale oil in margarine and soaps. Environmental laws and hunting limits have slowly allowed whale populations to recover.
    Blubber, right, is a better insulator than coats and jackets, left.

    Not All Fat is Blubber
    Blubber is different than most types of fat. Blubber is much thicker and contains many more blood vessels than the fat found in land animals, including humans.

    Blubber is so unique that many marine biologists don't refer to blubber as fat at all. To them, blubber is a unique type of connective tissue between the animal's skin and its internal organs.

  • Term Part of Speech Definition Encyclopedic Entry
    adipose adjective, noun

    animal fat stored in tissues in the body.

    anatomy Noun

    structure of an organism.

    ancient Adjective

    very old.

    Antarctic Noun

    region at Earth's extreme south, encompassed by the Antarctic Circle.

    Arctic Noun

    region at Earth's extreme north, encompassed by the Arctic Circle.

    Encyclopedic Entry: Arctic
    augment Verb

    to enlarge or add to.

    biomagnification Noun

    process in which the concentration of a substance increases as it passes up the food chain.

    blood vessel Noun

    tubes through which blood circulates.

    blubber Noun

    thick layer of fat under the skin of marine mammals.

    Encyclopedic Entry: blubber
    buoyancy Noun

    the power to float or rise in a fluid.

    cancer Noun

    growth of abnormal cells in the body.

    characteristic Adjective

    particular feature of an organism.

    chemical property Noun

    unique identity of a substance expressed by its type and arrangement of molecules.

    citrus Noun

    type of fruit tree, including lemon and orange.

    collagen Noun

    fiberous protein common in bone, skin, and connective tissue.

    concentration Noun

    measure of the amount of a substance or grouping in a specific place.

    conserve Verb

    to save or use wisely.

    constrict Verb

    to get smaller.

    culture Noun

    learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

    dense Adjective

    having parts or molecules that are packed closely together.

    diet Noun

    foods eaten by a specific group of people or other organisms.

    Encyclopedic Entry: diet
    dwindle Verb

    to shrink.

    Eskimo Noun

    people and culture native to the Arctic region of eastern Russia, the U.S. state of Alaska, Canada, and Greenland.

    fat Noun

    material found in organisms that is colorless and odorless and may be solid or liquid at room temperature.

    food chain Noun

    group of organisms linked in order of the food they eat, from producers to consumers, and from prey, predators, scavengers, and decomposers.

    Encyclopedic Entry: food chain
    food web Noun

    all related food chains in an ecosystem. Also called a food cycle.

    Encyclopedic Entry: food web
    fur Noun

    thick hair covering the skin of an animal.

    indicate Verb

    to display or show.

    indigenous Adjective

    characteristic to or of a specific place.

    Encyclopedic Entry: indigenous
    insulate Verb

    to cover with material to prevent the escape of energy (such as heat) or sound.

    Inuit Noun

    people and culture native to the Arctic region of Canada, Greenland, and the U.S. state of Alaska.

    lard Noun

    fat from animals used to flavor food.

    lipid Noun

    one of a large group of organic compounds including fats, oils, waxes, sterols, and triglycerides.

    lucrative Adjective

    profitable or money-making.

    mammal Noun

    animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

    marine mammal Noun

    an animal that lives most of its life in the ocean but breathes air and gives birth to live young, such as whales and seals.

    muktuk Noun

    traditional Eskimo and Inuit meal of frozen whale blubber and skin.

    nursing mother Noun

    female mammal who is feeding her offspring on milk she produces.

    nutrient Noun

    substance an organism needs for energy, growth, and life.

    Encyclopedic Entry: nutrient
    offspring Noun

    the children of a person or animal.

    PCB Noun

    (polychlorinated biphenal) chemical substance that can occur naturally or be manufactured that may cause cancer.

    PCB Noun

    (polychlorinated biphenal) chemical substance that can occur naturally or be manufactured that may cause cancer.

    pollution Noun

    introduction of harmful materials into the environment.

    Encyclopedic Entry: pollution
    predator Noun

    animal that hunts other animals for food.

    protein Noun

    one of many complex compounds, made of chains of amino acids, that make up the majority of all cellular structures and are necessary for biological processes.

    reduce Verb

    to lower or lessen.

    render Verb

    to convert animal fats, such as lard or blubber, into an oil by heating it over a low temperature.

    right whale Noun

    marine mammal native to the Atlantic and Pacific oceans.

    skin Noun

    soft external covering of some animals.

    sophisticated Adjective

    knowledgeable or complex.

    store Verb

    to keep for future use.

    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    toxic Adjective


    trypot Noun

    large iron pot used to boil blubber to make whale oil.

    vitamin C Noun

    chemical substance important for health. Also called ascorbic acid.

    warm-blooded Adjective

    able to keep a constant body temperature.

    whale oil Noun

    wax obtained from boiling the blubber of whales.

    whaling Noun

    industry of hunting whales.