For many thousands of years, caribou have been awakening the quiet world of the north as they've journeyed across the landscape during their annual migrations. In fact, caribou bones in northern Alaska have been dated to at least 28,000 years ago, during the late Pleistocene, when they shared the tundra with long-vanished mammoths and mastodons.

More than anything else, what distinguishes this member of the deer family from all other mammals of the north is their nearly continuous movement.

For example, moose tend to stay in one area to feed—some even spending their whole lives within a five mile area—but caribou are constantly on the go, dancing across the land, from wintering grounds, to calving grounds, to their summer range, and back again.

Caribou don't travel in a straight line either, so they cover many more miles than the distance between summer and winter ranges would indicate. In fact, satellite tracking has shown that caribou in the Porcupine herd travel more than 3,000 miles during their annual migration from the boreal forest in Canada to the North Slope of Alaska.

It's a sure thing that caribou will migrate, but their exact route is another question entirely. Trying to guess what mountain pass, what valley, what river a caribou herd might cross is anything but an exact science…hunters know well that expecting a caribou herd to take the same route twice is a recipe for a hungry winter. This scattered and varied travel also helps protect the slow-growing and fragile tundra plants—on which caribou depend—from overgrazing.

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