Visitors to Yellowstone quickly become aware of the various heat loving microorganisms that help give the thermal features such marvelous color and texture. However when the winter snow descends on the park, it becomes clear that the thermals play an important role in supporting the ecological diversity of the park. For example, otters remain at West Thumb throughout the winter because underwater thermal features create small patches of water on Yellowstone Lake that do not freeze. The park interior is able to support much larger numbers of bison and elk than it otherwise would because the thermal features keep snow cover down, or even non-existent, in the most brutal of winter storms. In turn, these populations support wolves - which have learned to hunt large game by driving them into the deeper drifts of snow.

In addition, thermal areas support many smaller organisms that could not survive Yellowstone's harsh winters - including several species of plants, insects, and the sagebrush lizard. Perhaps the effects of the geothermal areas are most pronounced in the rivers, like the Gibbon and Firehole, that receive a steady influx of warm water. Kept free of ice throughout the winter, and with sudden changes in chemistry and temperature, these larger rivers become, in effect, a rainbow ribbon of different, smaller rivers. As a consequence, the park maintains a greater diversity of aquatic plants, insects and other organisms than could hope to make it through a frozen Yellowstone winter.

Supporting everything from wolves and bison to aquatic plants and insects, the thermal features of the park are crucial in keeping the entire ecosystem diverse and healthy. Winter can be the best time of year to see the how these features help make Yellowstone so biologically diverse.

Great food, stories, and history make a memorable feast in The Yellowstone National Park Cookbook by Durrae Johanek. Treat yourself to 125 unique recipes culminated from more than a dozen park employees. Enjoy reading about Yellowstone while preparing recipes from personalities ranging from Yellowstone Superintendent Suzanne Lewis to Yellowstone Association employee Carolyn Wallen. From Mudpot Stroganoff to Mama Bear's Lasagna each dish has its own flavor of Yellowstone. Price $19.95 (member price $16.95)

Most people join the Yellowstone Association to support our mission of fostering the public's understanding, appreciation, and enjoyment of Yellowstone National Park and its surrounding ecosystem. With the help of our membership, we can send a strong message of support for America's remaining wild places. Join today and receive benefits such as a 15% discount on retail items at Park Stores and our website, an annual subscription to our quarterly magazine, Yellowstone Discovery, seasonal lodging discounts at selected park hotels during the spring, fall, and winter, and special enrollment opportunities for Institute courses.

Join the Institute this February 17-18 for bird watching on the Northern Range. Eagles, swans, dippers, and grouse: winter doesn't slow these birds down at all. Find out why some birds stay in Yellowstone year- round and other birds fly in for the coldest season. You'll learn to identify many of these winter species, observe their behavior, and discover their fascinating winter survival strategies through class sessions and field trips. If you are a beginning to intermediate birder, this course is for you! Shared student cabins are available in the heart of the Lamar Valley. The tuition cost is $180 ($170 for members) and cabins are $25 per night per person.

Don't forget that summer registration for Institute field seminars begins Monday, January 7th at 8 a.m. mountain time for members of the Yellowstone Association. Course fill fast so be sure to sign up early.