Musk-ox, caribou, and reindeer are the dominant large grazers, feeding on grass, sedge, lichen, and willow. Arctic hare, or snowshoe rabbit, and lemming feed on grass and sedge. Predators include the wolf, artic fox, and snowy owl. Polar bears, and sometimes brown bears are seen. Many birds nest in the tundra shrubbery in summer, migrating to milder climates before the winter season sets in.
Invertebrate life is scarce, but insects such as black flies and mosquitoes are abundant.
Alpine animal life includes the mountain goat, big-horned sheep, pika, marmot, and the ptarmigan, a grouselike bird. Flies are scarce but butterflies, beetles, and grasshoppers are abundant. The tundra ecosystem is extremely sensitive to disturbance with little ability to restore itself. Disruption of vegetative cover causes permafrost to melt deeply, causing collapse of ground and loss of soil. Automobile tracks cause deep gullies that persist for years.