Back Tundra biomes cover about 10 percent of the Earth's surface. In the United States, tundra biomes are found only in parts of Alaska. (Recall that Alaska is in the polar climate zone.) The climate of a tundra is extremely cold and dry. In fact, you could think of a tundra as a cold desert. Less than 25 centimeters of rain and snow fall on a tundra during most years.

(On the average, a snowfall 10 centimeters deep is the equivalent of I centimeter of rainfall.) The little water that is found on a tundra is permanently frozen in the soil. This frozen layer of soil is called permafrost. Almost 85 percent of the ground in Alaska is permafrost. Plant life on a tundra consists mostly of mosses and grasses. Carpet like lichens, which are actually fungi and algae growing together, cover the rocks and bare ground. Because of the permafrost, large trees cannot root on a tundra. The few trees that do grow here are mainly knee-high willows and birches.    One of the most recognizable of the animals is the tundra is the carribou, also known as the reindeer. I wonder if Santa ever hitched this baby up to a sleigh?

British soldier lichen (top) are common on the tundra as are tundra willow, dwarf birch, and sedge (bottom).

Lichens are the favorite food of caribou herds. The caribou roam the tundras in the summer before moving farther south for the winter. Wolves often follow close behind the caribou, preying on the old and weak animals. Birds such as ptarmigan and small animals such as lemmings also inhabit the tundras. Some animals are only seasonal residents of the tundras. Arctic terns, for example, make round trip migrations of 34,000 kilometers to mate and raise their young during the short tundra "summer."

The Alaska tundra is home to the white-tailed ptarmigan, the arctic tern, and the shaggy musk ox.

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