Late summer and Autumn is that time of year when a young bison's fancies turn to thoughts of love and, consequently, they get preternaturally grumpy. During the rut, bison are temperamental, territorial, and randy. It's not a good time to mess with them, and that goes for elk too. Give them a nice wide berth.
The tourists in this video, filmed in Lamar Valley, WY, shows bison walking on the road, and you can tell they're getting kinda irritated. The highlight of the video is undoubtedly the short little dance of annoyance performed one of the bison in the video after several of the other males blocked his path on the road.