Question

What is blubber and how does it help polar bear

Answer 1

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.

Insulation
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 furcoat, 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.

Buoyancy
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.