The Library of Congress >> Research Centers >> Science Reference Services

Everyday Mysteries: Fun Science Facts from the Library of Congress

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. See the following Web sites for information and additional links:

Debunking the Myth of Polar Bear Hair - Article 1390 from the Alaska Science Forum
http://www.gi.alaska.edu/ScienceForum/ASF13/1390.html

Complete Polar Bear Fact and Story Web site http://www.geocities.com/mikepolarbear/big_guess.html

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.

Related Web Sites

What is the largest bear on earth? - Everyday Mysteries: Fun Science Facts from the Library of Congress.
Polar Bears International - Polar Bear International is a non-profit group dedicated to the conservation of the polar bear. Web site includes bear facts, photographs, information and research.
Polar Bears: National Wildlife Federation - This Web site from the National Wildlife Federation contains the following categories: polar bear facts, behaviors, magazine articles, polar bear conservation, and activities for kids and parents.
What has been happening to polar bears in recent decades? From NOAA Arctic Theme pages. In addition to discussing the ecology of polar bears, this Web site provides a gallery of polar bear photographs and links for more information about polar bears and climate change.