During the winter season, bison head to lower ground in the North area of Yellowstone. The snow and temperatures are milder there and it’s easier to feed on grass under the snow. This can mean that hundreds of bison migrate to Lamar Valley, Mammoth Hot Springs, Old Faithful area, and sometimes cross Yellowstone’s border into Montana farmland. To avoid contact with livestock, states work with Yellowstone to keep the herds near the border and direct livestock to other grazing grounds. This also helps the bison have a shorter return to Yellowstone in warmer weather.
Watch the video below to see how bison shovel snow with their heads to reveal grass underneath. This is why bison often have their heads covered in snow and it can make quite a comical sight. In deep snow, bison have been known to dig as far as four feet into the snow to get to their meal.