Arctic National Wildlife Refuge

Dall Sheep are among the diverse species that inhabit the refuge.

Polar bears den on the refuge's coastal plain.

A wildlife biologist bands a peregrine falcon chick.

The Arctic National Wildlife Refuge, in the northeast corner of Alaska, contains boreal forests, arctic tundra and the highest peaks of the Brooks Range mountains.

The refuge is home to free-roaming herds of moose, Dall sheep, wolves and such solitary species as wolverines and polar and grizzly bears. About 194 bird species also have been seen there.

Winter on the refuge is long and severe; summer is brief and intense. Snow usually covers the ground about nine months of the year. Arctic plants have adapted to survive in an environment where permafrost is within 1.5 feet of the surface.

The annual growth of trees and shrubs is slight. It may take 300 years for a white spruce at treeline to reach a diameter of five inches. Small willow shrubs may be 50 to 100 years old.

The refuge protects a large portion of the calving grounds, wintering areas and migration routes of the 123,000-member Porcupine caribou herd, one of the largest herds in Alaska. Twice a year the herd migrates more than 400 miles between its calving and wintering areas.

Trips into this vast and remote wilderness should be carefully planned; the refuge has no roads, developments or trails. Visitors should be completely self-sufficient. Activities include hiking, backpacking, river floating, hunting, fishing and wildlife observation.