Spilling Thought: "All summer long, bison eat the cereal. In winter, they eat the box." As the snow flies in #Yellowstone, #bison work harder and harder to find food. They sweep their giant, wedge-shaped heads back and forth, pushing into the snow until they reach what's left of last summer's grass: an excercise that often leaves them malnourished come spring. Want more photos? Follow @yellowstonenps (NPS photo by Neal Herbert). by usinterior