Plight of the Polar Bear

Plight of the Polar Bear

Introduction Venture into the vast snow-covered winter tundra of the northern Arctic and you will be surprised by the apparent absence of life. This region is a harsh, unfriendly place for most living things. But one living thing has managed to thrive in the tundra--that is, until now.

Tundra: Winter Versus Summer During much of the year, the temperature in the tundra is extremely low-well below freezing. Winter lasts for more than six months, and for several weeks during that time the sun never rises above the horizon. The soil just below the surface remains permanently frozen throughout the year. And to make conditions even harsher, there are no barriers like trees or hills to slow down the cold winds that sweep across this ice and snow- covered land.

Summer in the tundra is quite a contrast from winter. The sun does not set for several weeks on end. Often it just peeks over the horizon, appearing to move as Earth rotates. During this season, the average temperature remains above freezing. The snow has a chance to melt, and low- growing plants such as mosses, lichens, grasses, and small shrubs grow. Millions of insects hatch and fill the air, ground, and pools of water. The abundance of insects attracts huge numbers of birds that migrate to the tundra and make it their summer home. Even mammals that migrated south to escape the harsh winter return to the tundra to feed each summer.

Yet despite the region's harsh conditions, one inhabitant lives there year round-one of Earth's most magnificent creatures, the polar bear. This creature of the North is well suited to the inhospitable conditions of the tundra, but in recent years the polar bears living along the northern edge of the tundra have been struggling to survive. The tundra's harsh conditions are not the reason--it is the Earth and its rapid alterations.

Built to Survive Polar bears are adapted to survive the severe conditions of the Arctic. They appear to be all white, but each strand of hair is actually transparent. It has been commonly believed that this clear fur carries sunlight to the bears' black skin, where it is absorbed and changed to heat. However, studies on polar bear fur have proven that it does not transmit sunlight to a bear's skin. Since the sun is either low on the horizon or not even above the horizon during the coldest Arctic months, it wouldn't make much difference if the fur was able to transmit sunlight to the bear's skin.