It's hard to impress a bison and not necessarily safe to try. You can ask a group of snowmobilers who just recently traversed Yellowstone National Park in a snowstorm. No, the bison they encountered was not impressed.
Stop me if you've heard this story before, but ranchers are trying to deal with wolves thinning their herds. Wyoming ranchers have been fighting this battle for almost 27 years. Now, it's Colorado ranchers that are having to deal with wolves and their livestock.