On our way out of Yellowstone National Park, there was a buffalo as big as our car, holding up traffic, it just took its time, and didn't let anyone pass him. It was funny as we got further down the traffic line and the people didn't know why they were inching along, they were mostly irritated not knowing that it was a buffalo doing it....we were glad we were on the other side, it was pretty cool to drive so close to it.