What Are the Adaptations of Native Animals in the Tundra?

Migration

• Caribou (large deer-like herd animals) travel hundreds of miles away from the tundra during the winter, and return in the summer to have their babies and breed next year's offspring. Many species of birds migrate to the tundra to spend the brief warm season feeding on abundant insects and fish, mating, nesting and raising their chicks. When the weather grows colder and the young are grown, both species travel back to warmer lands, only to repeat the cycle.

Hibernation

• Some tundra animals, such bears (brown and grizzly), sleep through the coldest weather in a den they partly find and partly make. Bears store food by eating voraciously in the spring and summer and growing a thick layer of fat under their skin to live off while they sleep. Lemmings and other small rodents build nests underground and rely on the snow to insulate them from extreme cold. They do not sleep in winter, as the bear does, but stay in their nests and eat the grass and seeds they harvested and stored during the summer.

Thermal Protection

• Many tundra animals have adapted to the harsh environment by growing thick fur coats, often in two layers -- a soft undercoat for insulation and a coarser outer coat for waterproofing. The musk ox grows so much hair that there is only a small area of bare skin between its nose and mouth. The arctic fox and the ptarmigan, a partridge-like bird, cover even their feet in winter; the fox with fur and the bird with feathers. To conserve body heat by reducing their surface area, tundra animals have developed rounder, chunkier bodies and smaller appendages such as legs, ears and tails.

Camouflage

• Tundra animals frequently change color with the seasons to become less conspicuous. The arctic hare changes from white in the winter, to blend into the snow, to gray-brown in the summer, to match the grass and leaves. Its main predator, the arctic fox, does the same. The ptarmigan also changes from brown to white for the winter. The polar bear, a true arctic animal, stays white year-round to maintain its camouflage because it lives and hunts most of its time at sea on the pack ice and comes to dry land as little as possible.