Donald M. Jones / American Bison (Bison bison) bulls, National Bison Range, Moise, Montana

Shin Yoshino / American Bison (Bison bison) silhouetted at dawn, Yellowstone National Park, Wyoming

Tim Fitzharris / American Bison (Bison bison) in winter, Yellowstone National Park, Wyoming

Tim Fitzharris / American Bison (Bison bison) herd grazing near Fountain Paint Pots, Yellowstone National Park, Wyoming

Jim Brandenburg / American Bison (Bison bison) pair grazing on prairie under an anvil cloud, Nebraska

Jim Brandenburg / American Bison (Bison bison) herd stampeding, South Dakota

Jim Brandenburg / American Bison (Bison bison) herd stampeding, South Dakota

Shin Yoshino / American Bison (Bison bison) herd drinking from lake, Yellowstone National Park, Wyoming

Yva Momatiuk & John Eastcott / American Bison (Bison bison) sub-adult bull, Theodore Roosevelt National Park, North Dakota

Donald M. Jones / American Bison (Bison bison) juvenile bulls sparring, western Montana

Sumio Harada / American Bison (Bison bison) sub-adult in snow, Yellowstone National Park, Wyoming

Sumio Harada / American Bison (Bison bison) calf running, Yellowstone National Park, Wyoming