Back in the Spring, the sighting of a white bison calf in Yellowstone garnered a lot of attention. Unfortunately beyond that initial sighting, it wasn’t seen again to my knowledge. But during the bison’s annual breeding season, or rut, which occurs in late July through August, the bulls will roll in dust and mud, often coating themselves and making them appear white. After a few rainy days which turned all the dust wallows into mud, many of the bulls were covered in dirt with this one being perhaps the whitest, or at least dirtiest of the bunch. The bull below is slightly cleaner.