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Polar Bear Invasion

Great Wanderers

The annual gathering of bears at the mouth of the Churchill River along Hudson Bay, featured on NATURE's POLAR BEAR INVASION, isn't just a boon for tourism. It is also a unique opportunity for researchers to study the bears and their behavior. Indeed, Canada's 15,000 polar bears are among the most studied on earth, and the nation's decades worth of bear data is the envy of biologists the world over.

The Churchill bears, for instance, have helped provide important insights into the bears' annual wanderings -- migrations that can take individual animals over thousands of miles of tundra and ocean and then back again. Some bears from eastern Canada even travel as far as Greenland and some islands off of Norway.

These days, however, one of the greatest concerns of researchers is understanding how a changing global climate may be affecting the bears. For example, some researchers believe that Hudson Bay's pack ice now melts about three weeks earlier each spring than it did just a few decades ago. In some recent years, the ice has broken up in March or April, shortening the bears' hunting season by several months and leaving them thin and weak. As a result, some studies suggest that the bears are getting smaller and having fewer cubs. Whether this is a short-term variation or a permanent problem remains to be seen.

Other scientists fear that pollution may be partly to blame. In some parts of Canada, winds, currents, or local industry add dangerous chemicals to the environment. These pollutants work their way up the food chain, accumulating in the fat of predator and prey alike. Even in the seemingly pristine tundra of Manitoba, for instance, bears can carry potentially harmful concentrations of chemicals.

Then there are concerns about the long-term impacts that Churchill's booming tourism trade is having on the bears. While officials attempt to strictly control access to the animals, there is little question that the bears see far more people than they did 100 years ago. And while the bears do not seem to fear people, the human presence could disturb mothers with cubs, forcing them to alter migration routes. So far, however, there is no clear evidence that tourism alone is harming the bears.

Indeed, Churchill's efforts to keep the bears at bay has had at least one positive side-effect: bears that may have once become accustomed to feeding at garbage piles or swiping food from kitchens, and then killed if they became a nuisance, now have fewer opportunities to get themselves into deadly trouble. Still, some researchers are watching closely to see if bear watching becomes a form of harrasment.

Luckily, polar bears have captured the attention of some policymakers. Under a 1973 treaty, known as the International Agreement for the Conservation of Polar Bears, the U.S., Russia, Canada, Denmark, and Norway work together to study and protect the animals. They have worked to limit bear hunting and control pollution. While these efforts have not always paid off, the world's 30,000 polar bears are -- for the moment -- holding their own.

Bear Trouble
Polar bears invade Churchill.

Great Wanderers
Discover what researchers are finding out.

Out On The Town
Learn why tourists visit Churchill.

Web links and books related to the program

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