Yellowstone National Park is known for its bison herds. We happened across a bison. He was separated from his herd. We first encountered him on a trail, we were going down and he was going up. We gave him wide berth and advised others around us and we waited. Others at the bottom of the trail must have crowded this fellow because he turned around and moved quickly towards them. We waited a few minutes and one of the crowd we were with moved down the trail to check out the situation. He waved us forward and this guy was behind the railing of the boardwalk. He posed for a little bit and then laid down. Ashton took this great picture. Never been that close to one of those animals...It is breathtaking.