Caribou in the Oil Patch

The Porcupine caribou herd, which migrates between Canada and the United States, is the world's largest transboundary caribou herd, generally ranging between 120,000 and 180,000 head over the past 25 years. It is named for the Porcupine River, which flows through its habitat. Like migrating birds, the herd moves northward in the summer and southward in the winter.