Its mating season in Yellowstone and the male bison are particularly aggressive at the moment. Just check this video posted by the park yesterday of a fight between two males that stropped traffic in Yellowstone. The park recommends staying at least 25 yards away from bison but currently I would consider a wider berth after watching this:
Bison mating is still going on in #Yellowstone. Male bison are particularly aggressive right now, though all bison and other wildlife can be dangerous. Always keep your distance—25 yards from #bison & elk; 100 yards from all other wildlife.#NationalPark #WhatWildlifeDoWednesday pic.twitter.com/IoVcAuPk8r
— Yellowstone National Park (@YellowstoneNPS) August 12, 2020