Mark MacEwen / Elk (Cervus canadensis) stag resting outside house during the rut, Estes Park, Larimer County, Rocky Mountains, Colorado, United States, September.

Erlend Haarberg / Male European elk / Moose (Alces alces) in undergrowth, Sarek National Park, Sweden, September

George Sanker / Elk / Wapiti (Cervus canadensis) herd with young on meadowland against the Grand Tetons, low clouds and the Snake River. Grand Teton National Park, Wyoming, USA, June.

Eric Baccega / Two Elk (Cervus canadensis) bulls at sunset, Jasper National Park, Rocky Mountains, Alberta, Canada, September

Shattil & Rozinski / Elk (Cervus canadensis) herd grazing, Horseshoe Park, Rocky Mountain NP, Colorado, USA

Donald M. Jones / American Elk (Cervus elaphus nelsoni) bull in velvet with Canadian Rockies backdrop, western Alberta, Canada

Tim Fitzharris / Stand of conifers in the Elk Mountains near Crested Butte, Colorado

Lynn M Stone / Elk deer {Cervus elaphus} stag in snow, Jasper NP, Canada

Mark Raycroft / Elk (Cervus elaphus) large bull standing alert in meadow with mountains behind

Chase Dekker / Elk (Cervus elaphus) herd crossing river, Snake River, Grand Teton National Park, Wyoming

Jeff Vanuga / Shiras moose (Alces alces shirasi) male, flehmen response / lip curling with mountains in background, Grand Teton National Park, Wyoming.

Igor Shpilenok / Woman petting Moose (Alces alces) on farm, Pechora-Ilichsky Nature Reserve, Virgin Forests of Komi UNESCO World Heritage Site, Russia's Ural Mountains. August 2016.