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    Is a polar bear’s fur transparent?


    Yes! Most sources indicate that the long, coarse guard hairs, which protect the plush thick undercoat, are hollow and transparent. The thinner hairs of the undercoat are not hollow, but they, like the guard hairs, are colorless.

The hair of a polar bear looks white because the air spaces in each hair scatter light of all colors. The color white becomes visible to our eyes when an object reflects back all of the visible wavelengths of light, rather than absorbing some of the wavelengths.

At one time it was suggested that the polar bear hairs might have some of the properties of optical fibers. Apparently this is not the case.

Scientists in the late 1970’s discovered another interesting tidbit about polar bears. A number of polar bears in zoos from around the world were turning green! These scientists discovered that the algae responsible for making the bears green were not on the SURFACE of the hairs, as originally supposed, but were INSIDE the hairs (Lewin & Robinson, 1979). The algae more than likely came from the pond waters in the bears’ enclosures.

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Library of Congress Web SiteFurther Reading
  • Brown, Gary. The great bear almanac. New York, Lyons & Burford, 1993. 325 p.
  • Bruemmer, Fred. How polar bears break the ice. Natural history, v. 93, December 1984: 38-47
  • Davids, R.C. Lords of the arctic: a journey among the polar bears. New York, MacMillan, 1982. 140 p.
  • Lewin, Ralph A., and Phillip T. Robinson. The greening of polar bears. Nature, v. 278, March 29, 1979: 445-447.
  • Patent, Dorothy Hinshaw. Polar bears. Minneapolis, Carolrhoda Books, c2000. 48 p. (Juvenile literature)

SearchFor more print resources...
Search on "polar bears" and "bears" in the Library of Congress Online Catalog.

Photo of an adult polar bear
Photo: NASA's Ocean Surface Topology from Space, from the NASA Website.

Photo of three polar bears on land, eating.
From the Arctic Theme Page at National
Oceanic and Atmospheric Administration,

Photo:  a polar bear on ice, surrounded by blue sea.
Photo from the NOAA Website.
http://www. monitoring

Polar Cub getting tagged for observation.
Cub being tagged for observation. NOAA Photo Library.

Photo: A young polar bear rests upon his mother's back.
A mother and her young. From the U.S. Fish
& Wildlife Service. Credit: Scott Schliebe.

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 The Library of Congress >> Researchers >> Science Reference Services
  February 6, 2012
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