Cover Caption

Cover: During winter in the interior of Yellowstone National Park most elk migrate from deep snow while many bison do not, existing near thermal areas and on wind-blown ridges. Wolves still attempt to kill these bison and often spend hours making a kill. Wolf-bison systems used to dominate in North America prior to European settlement but now only Yellowstone and Wood Buffalo National Parks have intact wolf-bison systems. See pp. 1105-1116. Photo by Doug Smith, National Park Service.