This beast of a bull bison has a hairstyle that could be from 1970s Harlem, not Yellowstone National Park. My guide - who is a seasoned visitor to the stretch of road between Madison and Old Faithful-had never seen him before.

This is surely a character from fantasy movie or Game of Thrones, not a regular member of the Yellowstone Club for bisons. He is the Thing from Wyoming.

The water is materially warmer than the daytime temperature which is why bison often congregate at the river banks during the mid winter and this was very much mid winter.