Big prairie animals help spread seeds on the prairie in two ways.
Many prairie seeds have little hooks on thorns on them. They hang in the fur of large prairie animals and drop off as they move about.
Big prairie animals swallows seeds of prairie plants as they graze. They digest the stalks and leaves, but many of the seeds pass through the animals and are eliminated in their droppings. As the animals move about the prairie, the seeds are scattered all about.