During the winter, the bison herd in Yellowstone National Park uses, Warm Stream, which does not freeze, as a path from one feeding ground to the next. After an unusually high snow fall, this bison found himself blocked and exhausted from pushing, throughout the day, against the narrowed snowpack. Due to the presence of a wolf pack not far away, his plight was highly uncertain. Just as he was ready to make another desperate push, he took one step backward and realized he could move and then proceeded to back out of his perilous position.