Do Polar Bears Keep Warm

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Penguins and polar bears live in some of the coldest climates on earth. In order to survive they need to be able to insulate and keep themselves warm.
For the last couple of weeks my class have been investigating how penguins and polar bears keep warm in the coldest temperatures. I am going to report how they do this and how polar bears keep warm and how this relates to penguins keeping warm.

How Penguins keep warm

Penguins use their feathers as insulators on land, instead of having the large flat feathers that flying birds have, penguins have short ones with an under layer of fine wooly down. This down creates a trapped layer of air which provides 80% to 84% of the thermal insulation for penguins. This layer of air is compressed during dives but can
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They are warm-blooded mammals, yet they live in the freezing Arctic. They have a thick coat of fur as well as a thick layer of fat under their skin, these both are very good insulators. One of the most interesting things about polar bears are their hairs. Polar bears actually have two types of fur: long oily guard hairs and short insulating hairs. Polar bears stay warm by combining the properties of these two hairs. The guard hairs are actually hollow. The guard hairs are filled with air and absorb the sun’s rays and provide a polar bear with warmth while also providing an oily outer layer which helps keep the polar bear dry. The insulating hairs helps polar bears warm by trapping heat close to the skin. Under their fur they have black skin which is good for absorbing the rays of the arctic sun. The black skin radiates heat but then the white hairs reabsorb it. The warmth that is reused heats up the thick layer of air trapped around the thick wooly underfur, this insulates the body from cooling down by conduction and convection of heat to the cold around it. On sunny days, the longer outer hair enables bear to use solar
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