Visitors To Japanese Zoo Ask Why Are The Polar Bears Green?

Algae-dyed polar bears puzzle Japan zoo visitors
(AP)

AP - Green-colored polar bears are drawing questions from puzzled visitors at a Japanese zoo.

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/AS...

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

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.

Aussie the Green Polar Bear, originally uploaded by Asten. Microscopic Algae gets into the hollow hairs and turns them green in the summer. It's harmless and goes away in the fall/winter.