Christmas in Yellowstone is a really beautiful video that is definitely worth a watch. The movie covers the history and wildlife of the park, in a season most visitors don't come around for. Only nature could make this stuff up-- absolutely breathtaking.
In the video John Colter and his exploration is mentioned- he was a member of the Lewis and Clark expedition- because he spent a winter in the area on his own. Colter was used as the subject of the novel, Wilderness.