For the bison, it will be a matter of brute strength.
Massive neck muscles enable them to shovel five tonnes of snow a day.
Their light-weight neighbour needs more precision.
The bison have reached their goal, a mouthful of withered grass.
And where the bison have dug, the fox now spots an opportunity.
Every footstep counts, but he mustn't break through... Yet.
He listens carefully to pinpoint his target. It's moving.
A vole. Small, but 100 times more nutritious than a mouthful of dried grass.
To get through the winter on these prairies, sometimes brain beats brawn.
Ultimately, life on all grasslands depends on the turn of the seasons.