American bison (Bison bison) running in the snow, Wyoming, USAAmerican bison (Bison bison) running in the snow, Wyoming, USA. At dusk, these bison went down a steep slope to join a larger herd in the valley. Because of their weight, they started running down the slope. They continued running in the flats towards the herd. The fresh snow made for nice powder. American bison (Bison bison) running in the snow, Wyoming, USAAmerican bison (Bison bison) running in the snow, Wyoming, USA. At dusk, these bison went down a steep slope to join a larger herd in the valley. Because of their weight, they started running down the slope. They continued running in the flats towards the herd. The fresh snow made for nice powder. American bison (Bison bison) running in the snow, Wyoming, USAAmerican bison (Bison bison) running in the snow, Wyoming, USA. At dusk, these bison went down a steep slope to join a larger herd in the valley. Because of their weight, they started running down the slope. They continued running in the flats towards the herd. The fresh snow made for nice powder. American bison (Bison bison) running in the snow, Wyoming, USAAmerican bison (Bison bison) running in the snow, Wyoming, USA. At dusk, these bison went down a steep slope to join a larger herd in the valley. Because of their weight, they started running down the slope. They continued running in the flats towards the herd. The fresh snow made for nice powder.