click on the image to view the mapped satellite data (1985-1990)

The Herd may winter in the Peel and Porcupine River watersheds (hence its name) in the Yukon Territory as well as in northeastern Alaska. The caribou spend up to eight months of the year in a snow-covered environment and are well-adapted to cope with winter. Their ability to sniff out food under the snow reduces time searching for the staple item of their winter diet--lichens. Lichens provide a highly digestible energy source, high in soluble carbohydrates but low in protein. The caribou do not move about much during winter.

The only intrusion into their winter range is the Dempster Highway which links Dawson City in the Yukon to the communities of the Mackenzie Delta.