American bison standing in field, National Bison Range, Montana, USA

Antlers in field, National Bison Range, Montana, USA

Mustang (Equus ferus caballus) standing on mountain, Mt Pryor, Wyoming, USA

Two Mustang (Equus ferus caballus) horses standing in field, McCullough Peaks, Wyoming, USA

Tree in field with mountain range in background, National Bison Range, Montana, USA

Taxi parked in row at taxi stand, Glacier National Park, Montana, USA

Two Exmoor Ponies (Equus ferus caballus) standing in a grassy landscape, Texel, Netherlands

Man standing on rock formation, Monument Valley, Arizona, USA

European bison (Bison bonasus) standing in field, Bavarian Forest, Bavaria, Germany

European elk (Alces alces) standing in forest, Chugach State Park, Alaska, USA

European bison (Bison bonasus) standing in forest, Bavarian Forest National Park, Bavaria, Germany

Three American Bison (Bison bison) grazing in filed, Yellowstone National Park, Wyoming, USA

European bison (Bison bonasus) standing in field with its calf, Bavarian Forest, Bavaria, Germany

Grizzly bear (Ursus arctos horribilis) standing with prey at riverbank, Denali National Park, Alaska, USA

Brown bear (Ursus Arctos) standing at riverbank, Brooks River, Katmai National Park, Alaska, USA

Moose (Alces alces) and two Red Deer (Cervus elaphus) standing at riverside, Yellowstone National Park, Montana, USA

Grizzly bear (Ursus arctos horribilis) standing with prey at riverbank, Denali National Park, Alaska, USA

Close-up of calf of American Bison (Bison bison) in field, Grand Teton National Park, Wyoming, USA

Bison standing on grassy landscape, USA