Here is a list of publications that will help you plan a safe, enjoyable Yellowstone adventure. Most of these publications are in PDF format and can be viewed or printed using Adobe Acrobat Reader (available free, online).
Resources and Issues - The handbook our naturalists use to answer many basic park questions. The book is updated annually.
Yellowstone Association Bookstore: Why wait until you are here to buy your Yellowstone books? Buy them in advance so you can read them on your way here.
Some groups of Shoshone Indians, who adapted to a mountain existence, chose not to acquire the horse. These included the Sheep Eaters, or Tukudika, who used dogs to transport food, hides, and other provisions. The Sheep Eaters lived in many locations in Yellowstone.