Bison graze near the U.S. Route 89 highway just outside of Gardiner, Mont., Monday, Feb. 14, 2011. Hundreds of bison have left the boundaries of Yellowstone National Park this winter in search of ... more 
Bison graze near the U.S. Route 89 highway just outside of Gardiner, Mont., Monday, Feb. 14, 2011. Hundreds of bison have left the boundaries of Yellowstone National Park this winter in search of food. less 
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Associated Press | Photo By Ted S. Warren
Thu, Feb 17, 2011 4:30 AM EST