Most visitors to Denali National Park and Preserve see the park's sled dogs during summer mushing demonstrations. Only a few visitors ever see Denali's dogs when their real work begins -- when park dog teams patrol thousands of miles under the extreme winter weather conditions of Interior Alaska.

This video captures the challenges, techniques and tradition of dog mushing in Denali as sled dogs and rangers patrol a spectacular winter landscape on their historic mission to preserve the wildlife and wilderness of Alaska's best-known national park.