There is just something about pictures of the American Bison that lends itself very well to monochrome treatment. I reckon it is as much as anything because we view it as a creature of the Old West.
It came close to disappearing back then due to over hunting but, thankfully, conservation efforts prevailed and now there are many of these scattered across the western United States in private and public herds. It used to be we called these buffalo but that actually was incorrect. While they are part of the same family that includes the European and African buffalo, the Bison is its own, distinct species.
It is believed they were called buffalo by early North American explorers due to their resemblance to the Old-World species. Native Americans call them Tatanka, a Lakota word that translated means “bull buffalo.” In May 2016 the Bison became the official mammal of the United States, a fitting and long overdue honor.