Air Date: Week of November 20, 1998

This week, facts about... Polar Bears.

Transcript

CURWOOD: Fifteen years ago this week, Canada, Denmark, Norway, and the United States signed a pack to protect polar bears and their habitat. So far the treaty has failed to stem habitat loss, although a hunting ban has helped to increase the bear population to about 30,000. By this time of year, pregnant polar bears have finished digging their dens, getting ready for cubs to be born. Tiny, blind, and hairless, the young will suckle their hibernating mothers until spring. Researchers in Norway recently found alarming levels of polychloride biphenyls, or PCBs, in polar bears. They also discovered some female polar bears had developed vestigial male sex organs, which may be a response to exposure to PCBs. Even though PCBs were banned in 1970, these chemicals persist in the environment. Over the years they have migrated thousands of miles to the Arctic from industrial sources Scientists are now studying the chemical's effect on the bears' immune and reproductive systems. One thing they do know: the PCBs tend to concentrate in mother's milk. So next spring, polar bear cubs will probably start life with heavy doses of the stuff. And for this week, that's the Living on Earth Almanac.