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Located in northern Manitoba on the west side of Hudson Bay, Churchill is out in the middle of nowhere. But polar bears like it that way. They spend summers on the tundra (苔原) around Churchill. In the fall, they wait anxiously along the shore of Hudson Bay for the ice to form. Then they go out onto the frozen sea to hunt ringed seals -- their favorite food. October and November are the best polar-bear viewing times. From tundra vehicles, visitors to Churchill observe the bears. Some enjoy day trips or stay overnight on large tundra vehicles that have private cabins and eating facilities. Others stay at a wilderness lodge on the bears' migration route to view the vigorous creatures. These lodges can be reached only by air and feature luxury food and living arrangements.

Despite the large number of polar bears that visit Churchill each year, there is growing concern about the animals' future. Because the earth is getting warmer, the ice forms later in the year now and disappears sooner in the spring. As a result, polar bears have less time to hunt for seals. Polar bears can also find smaller animals, bird eggs and berries on land, but this kind of food is not sufficient to support the animals.

Polar bears are also affected by plastic and chemicals that get into the ocean. A research project carried out in northern Europe has found high concentrations of both plastic and chemicals in the tissue of polar bears. These materials and substances can damage the animals' internal organs, especially when the animals are not yet mature. Many people are researching polar bear health. Their goal is to gather the information that is needed to help save these animals.