The Mudcat Café TM
Thread #44716   Message #659864
Posted By: SharonA
28-Feb-02 - 09:41 AM
Thread Name: BS: Mental Workouts without Dilbert
Subject: RE: BS: Mental Workouts without Dilbert
GUEST: Mine would! *G*

Wolfgang's right; the answer to the question as posted is the South Pole... and I don't believe there are any bears (polar or otherwise) at the South Pole.

As for the color of the polar bear, it is not white, contrary to popular belief. Here's an excerpt from this page: http://www.polarbearsalive.org/facts3.htm (probably more than anyone wanted to know, but here it is anyway)....


POLAR BEAR FUR

* Despite what our eyes tell us, a polar bear's fur is not white. Each hair shaft is pigment-free and transparent with a hollow core.
* Polar bears look white because the hollow core scatters and reflects visable light, much like ice and snow does.
* When photographed with film sensitive to ultraviolet light, polar bears appear black.

     Early speculation over this discrepancy produced a theory, now widely repeated as fact, that polar bear hair acts like a fiber optic guide to conduct ultraviolet light to the skin.
     In 1998, Daniel W. Koon, a physicist at St. Lawrence University in Canton, New York, decided to actually test whether or not polar bear hair could efficiently conduct ultraviolet light.
     Koon and a graduate assistant, Reid Hutchins, obtained polar bear hair from the Seneca Park Zoo in Rochester. Their experiments showed that a one-fifth inch strand of polar bear hair was able to conduct less than a thousandth of a percent of the applied ultraviolet light. With such a high loss rate, meaningful amounts of ultraviolet light cannot be reaching a polar bear's skin.
     Instead, Koon believes the ultraviolet light is absorbed by the keratin making up the hair.

* In 1979, three polar bears at the San Diego Zoo turned green. Scientists discovered that colonies of algae were growing in the bears' hollow hair shafts.
* Although the algae in no way harmed the animals, zoo veterinarian Phillip Robinson restored the bears' "white" fur by killing the algae with a salt solution.
* The fur on a polar bear cub [appears] whiter than that of adult bears. In older bears, [apparent] fur colors range from white to almost yellow.
* Hybrid cubs born to captive polar bears and their close relative, the brown bear, are "white" at birth but later turn blue-brown or yellow-white [I wonder if this means that some pigment enters the hair shaft?].
* A polar bear is so well-insulated that it experiences almost no heat loss. In addition to its insulating fur, the bear's blubber layer can measure 4.5 inches thick.
* So effective is the polar bear's insulation that adult males quickly overheat when they run [All the same, I wouldn't try to outrun one if I were you].
* Because polar bears give off no detectable heat, they do not show up in infrared photographs. (Infrared film measures heat.) When a scientist attempted to photograph a bear with such film, he produced a print with a single spot -- the puff of air caused by the animal's breath.

Sources: Lords of the Arctic by Richard C. Davids (Macmillan Publishing, 1982); Polar Bears by Ian Stirling (University of Michigan Press, Ann Arbor, 1988); Daniel W. Koon, "Is Polar Bear Hair Fiber Optic?", Applied Optics, Vol 37, page 3198.