Unlike the summer months when the national parks are teaming with visitors, winter brings far fewer visitors. In fact, in Yellowstone NP, the public is required to enter the park only with a licensed guide from December 15 through March 15. It’s easy to see why with the amount of snowfall that the park gets. For us, traveling in the park in winter requires specialized vehicles - snow coaches. For the animals it all about surviving winter in Yellowstone National Park.