The polar tundra is the coldest of all Earth's climates with cold desert-like conditions. Rainfall is sparse and the growing season is short. Because of these factors, animal inhabitants of the tundra have been conditioned to handle long, cold winders. They often have additional fat insulation to keep them warm, and many species hibernate or migrate south during the winter. Most tundra animals give birth and raise their young quickly in the summer.
Forty-eight species of land mammals inhabit the tundra. Most hibernate during the winter because of the very cold climate. Though 48 is a relatively low number for a region as large as the polar tundra, the species that do inhabit this region are found in large numbers. Tundra mammals include arctic foxes, wolves, polar bears, and even brown and grizzly bears. Also found in the tundra are lemmings, voles, caribou, arctic hares, musk oxes and squirrels.
Most polar tundra birds are migratory, appearing in the tundra only during the warm season. These migratory birds include ravens, snow buntings, falcons, loons, sandpipers, terns, snow birds, and gulls. Also found in the tundra is the snowy owl and the harlequin duck.
Though not that many species of fish inhabit the tundra, there are some common species that can be found in this region. Cod, flatfish, salmon, and trout are all inhabitants of the tundra, and serve as prey for polar bears and other larger animal inhabitants of the region.
There are insects in the cold climate of the polar tundra. Insect inhabitants of this region include mosquitoes, flies, moths, grasshoppers, blackflies and arctic bumble bees.