秋季迁徙时正在游过科伯克河的驯鹿，阿拉斯加 Caribou swimming across Alaska's Kobuk River during fall migration (© Michio Hoshino/Minden Pictures)

秋季迁徙时正在游过科伯克河的驯鹿，阿拉斯加 Caribou swimming across Alaska's Kobuk River during fall migration (© Michio Hoshino/Minden Pictures)

Caribou on the move

Each fall a quarter million caribou come together to form the Western Arctic Caribou Herd, a group that makes an epic migration through northwest Alaska. In great numbers they move south from their calving grounds in the Utukok River Uplands to their winter range on the Seward Peninsula. Fall is also the time when scientists attach radio collars to members of the herd, to track their location and health, and to gain information that will help conserve the species. When spring arrives, they'll complete the trip again in reverse, covering a total of 2,000 miles each year, give or take.

One of the best spots to see the herd on the move is where the great masses of animals cross this river, the Kobuk, at Onion Portage. The name of the portage derives from an Inupiaq (Inuit) word meaning 'wild onions' for the many wild onions that grow here. But the native Inuit people don't come here just to forage for onions. For millennia, the caribou crossing has drawn native peoples who rely on caribou meat, a tradition that continues to this day.