George Sanker / Newborn Elk (Cervus canadensis) calf looks up to its mother, Yellowstone National Park, USA, June

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.

Jeff Vanuga / Elk (Cervus canadensis) wintering on the National Elk Refuge, Jackson, Wyoming, USA, February.

Charlie Summers / Elk / Wapiti (Cervus canadensis) stag Bull standing on snowy ridge, Yellowstone National Park, Wyoming, USA

Russell Laman / Elk (Cervus canadensis) in a snowstorm. National Elk Refuge, Jackson Hole, Wyoming, USA. HIGHLY COMMENDED: Ten years and under in the Young Wildlife Photographer of the Year competition 2010

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

Jeff Vanuga / Silhouette of male Elk {Cervus canadensis} at dawn, crossing meadow in Yellowstone National Park, Wyoming, USA, September

Jeff Vanuga / Female Elk {Cervus canadensis} amongst wildflowers in spring, Mammoth area of Yellowstone National Park, Wyoming, USA, June

Jeff Vanuga / Two male Elk {Cervus canadensis} in velvet, resting in foggy meadow at dawn, Yellowstone National Park, Wyoming, USA, July

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

Rolf Nussbaumer / Elk / Wapiti {Cervus canadensis} bull bugling beside cow amongst aspen trees, Rocky Mountain National Park, Colorado, USA, September 2006

George Sanker / Elk or Wapiti (Cervus canadensis) calf grooming by river. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Elk / Wapiti (Cervus canadensis) resting by water, calf waiting for mother. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Coyote (Canis latrans) with Elk (Cervus canadensis) calf prey. Yellowstone National Park, Wyoming, June.

George Sanker / Bull Elk (Cervus canadensis) resting by water. Autumn in Banff National Park, Alberta, Canada, October.

Danny Green / Elk stag (Cervus canadensis), adult in snow. Yellowstone, United States America, February.

Peter Cairns / Bull Elk (Cervus elaphus canadensis), Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Tourists watching Elk (Cervus elaphus canadensis), Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) grazing on lawn in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Rutting bull Elk (Cervus elaphus canadensis) near Do Not Approach Elk sign in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Rutting bull Elk (Cervus elaphus canadensis) in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Tourist photographing Elk (Cervus elaphus canadensis) next to do Not Approach Elk sign, Mammoth Hot Springs, Yellowstone National Park, USA. October 2008.

Peter Cairns / Elk (Cervus elaphus canadensis) young on terrace of house, Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) copulating on lawn in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Park Ranger keeping an eye on Elk (Cervus elaphus canadensis), Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) herd resting in front of hotel, Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) female grazes on lawn at night, Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) grazing on lawn in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) rutting bull in town of Mammoth Hot Springs, Yellowstone National Park, USA

Peter Cairns / Elk (Cervus elaphus canadensis) rutting bull crossing road, Mammoth Hot Springs, Yellowstone National Park, USA

George Sanker / Elk (Cervus canadensis) bull portrait, Banff NP, Alberta, Canada

Todd Mintz / Elk (Cervus canadensis) male, sitting in grassland, Banfff National Park, Alberta, Canada.

Todd Mintz / Elk (Cervus canadensis) male standing piortrait, Banff National Park, Alberta, Canada.

Todd Mintz / Elk (Cervus canadensis) standing portrait, Banff National Park, Alberta, Canada.

Todd Mintz / Elk (Cervus canadensis) male from behind, standing, Banff National Park, Alberta, Canada.

George Sanker / Elk (Cervus canadensis) herd silhouetted on horizon, USA, October

George Sanker / Bull Elk (Cervus canadensis) lying down in approaching spring storm, Yellowstone National Park, Wyoming, USA, June

Kirkendall-Spring / Elk (Cervus canadensis) grazing in meadow along the High Divide in Olympic National Park, Washington, USA, July 2009

George Sanker / Portrait of a bull Elk / Wapiti (Cervus canadensis). Yellowstone National Park, Wyoming, USA, October.

George Sanker / Elk / Wapiti (Cervus canadensis) mother grooming young calf. Yellowstone National Park, Wyoming, USA, May.

George Sanker / Elk / Wapiti (Cervus canadensis) bull with his harem of females. Yellowstone National Park, Wyoming, USA, October.

George Sanker / Elk / Wapiti (Cervus canadensis) stag with large antlers at riverside. Gardiner River, Yellowstone National Park, Wyoming, USA, September.

George Sanker / Elk / Wapiti (Cervus canadensis) bull with harem by the Gardiner River. Yellowstone National Park, Wyoming, USA, September.

George Sanker / Elk / Wapiti (Cervus canadensis) herd crossing a meadow. Yellowstone National Park, Wyoming, USA, June.

George Sanker / Elk or Wapiti (Cervus canadensis) mothers with their young calves crossing the Snake River. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Elk / Wapiti (Cervus canadensis) on the banks of the Snake River. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Elk / Wapiti (Cervus canadensis) mother with newborn calf crossing the Snake River. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Elk / Wapiti (Cervus canadensis) with young set against vast mountain landscape with low clouds. Grand Teton National Park, Wyoming, USA, June 2011.

George Sanker / Elk / Wapiti (Cervus canadensis) mothers with newborn calves crossing the Snake River. Grand Teton National Park, Wyoming, USA, June.

George Sanker / Elk / Wapiti (Cervus canadensis) mothers and young calves on the banks of the Snake River. Grand Teton National Park, Wyoming, USA, June.

Charlie Summers / Two bull Elk (Cervus canadensis) with velvet antlers. Wind Cave National Park, South Dakota, USA, May.

Jeff Vanuga / A herd of Elk (Cervus canadensis) in snow. Dubois, Wyoming, USA, February.

Jeff Vanuga / A herd of Elk (Cervus canadensis) in snow. Dubois, Wyoming, USA, February.

Charlie Summers / Elk (Cervus canadenis) bull stamping, asserting his dominance, Yellowstone NP, Montana, USA

Charlie Summers / Bull Elk (Cervus canadensis) standing, posturing in Madison river, Yellowstone NP, Montana, USA

Charlie Summers / Bull Elk (Cervus canadensis) standing in Madison river, Yellowstone NP, Montana, USA

Charlie Summers / Bull Elk (Cervus canadensis) jumping into Madison river, Yellowstone NP, Montana, USA

Charlie Summers / Bull Elk (Cervus canadensis) in Madison river, Yellowstone NP, Montana, USA

Charlie Summers / Bull Elk (Cervus canadensis) with eight point antlers, resting with Rocky mountain background, Montana, USA

Charlie Summers / Elk (Cervus canadensis) bull crossing the Madison River of Yellowstone National Park, Wyoming, USA, October

Konstantin Mikhailov / Wapiti / Elk (Cervus canadensis) female grazing in Olympic National Park, NW America, Washington state. October.

Aflo / Four Elk (Cervus canadensis) lying, Yellowstone National Park, USA

Patricio Robles Gil / Bull elk (Cervus canadensis) portrait, during the rut, Grand Teton National Park, Wyoming, USA, October

Patricio Robles Gil / Elk (Cervus canadensis) herd at wintering ground where they are fed, Wild River Range, Wyoming, USA, January

Patricio Robles Gil / Female Elk (Cervus canadensis) group walking through snow, Wild River Range, Wyoming, USA, January

Patricio Robles Gil / Young female Elk (Cervus canadensis) walking through snow, Wild River Range, Wyoming, USA, January

George Sanker / Elk (Cervus canadensis) herd in snow at dusk, Grand Teton National Park, Wyoming, USA, June 2008

George Sanker / Grey wolf (Canis lupus) pulling at Elk (Cervus canadensis) carcass killed by its pack, Yellowstone National Park, Wyoming, USA, May

George Sanker / Elk (Cervus canadensis) cow sniffing air, part of mating behavior, Banff National Park, Alberta, Canada, September

George Sanker / Grizzly bear (Ursus arctos horribilis) looking for Elk (Cervus canadensis) calves while an adult watches from a distance, Yellowstone National Park, Wyoming, USA, June

George Sanker / Elk (Cervus canadensis) licking newborn calf, Yellowstone National Park, Wyoming, USA, June

George Sanker / Young Grizzly bear (Ursus arctos horribilis) standing over bull Elk (Cervus canadensis) carcass, Yellowstone National Park, Wyoming, USA, June

Eric Baccega / Bull Elk (Cervus canadensis) Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Two bull Elk (Cervus canadensis) sparing in the mating season, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Two bull Elk (Cervus canadensis) sparing in the mating season, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Male Elk (Cervus canadensis) in rut season, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Bull elk (Cervus Canadensis) crossing highway, with two people taking photographs out of parked car, Jasper National Park, Rocky mountains, Alberta, Canada, September 2009

Eric Baccega / Bull Elk (Cervus canadensis) walking near river, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Bull Elk (Cervus canadensis) portrait, Jasper National Park, Rocky Mountains, Alberta, Canada, September

Eric Baccega / A bull Elk (Cervus canadensis) standing near a river, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Two bull Elk (Cervus canadensis) sparing in the mating season, Jasper National Park, Rocky Mountains, Alberta, Canada

Eric Baccega / Elk (Cervus canadensis) pair in rut season, Jasper National Park, Rocky Mountains, Alberta, Canada

Jeff Vanuga / Elk {Cervus canadensis} herd on migration in spring out of the National Elk Wildlife Refuge through Grand Teton National Park, Wyoming, USA, May 2009

Jeff Vanuga / Elk {Cervus canadensis} stag bugling during the autumn rut with females in the background, Grand Teton National Park, Wyoming, USA, October 2008

Jeff Vanuga / Elk {Cervus canadensis} herd on migration in spring out of the National Elk Wildlife Refuge through Grand Teton National Park, Wyoming, USA, May 2009

Jeff Vanuga / Two Female Elk {Cervus canadensis} amongst wildflowers in spring, Mammoth area of Yellowstone National Park, Wyoming, USA, June

Jeff Vanuga / Tourist watches Elk {Cervus canadensis} crossing the road in Yellowstone National Park, Wyoming, USA, October 2008

Jeff Vanuga / Elk {Cervus canadensis} female trapped in a corale by the US Fish and Wildife Service and the Wyoming Game and Fish Department await testing by researchers for brucillosis disease. National Elk Refuge...

Jeff Vanuga / Vehicles approach a herd of Elk {Cervus canadensis} on migration in spring out of the National Elk Wildlife Refuge through Grand Teton National Park, Wyoming, USA, May 2009

Jeff Vanuga / Elk {Cervus canadensis} trapped in a corale by the US Fish and Wildife Service and the Wyoming Game and Fish Department await testing by researchers for brucillosis disease. National Elk Refuge, Jacks...

Jeff Vanuga / Elk {Cervus canadensis} stag crossing the Madison River during the autumn rut, Yellowstone National Park, Wyoming, USA, September

Shattil & Rozinski / Two male Elk (Cervus canadensis) fighting, Horseshoe Park, Rocky Mountain National Park, Colorado, USA

Shattil & Rozinski / Male Elk (Cervus canadensis) portrait, Horseshoe Park, Rocky Mountain National Park, Colorado, USA, Autumn

Tim Laman / Tule elk (Cervus elaphus nannodes) stags, an endemic subspecies found only in California. Point Reyes National Seashore, California.

Tim Laman / Tule elk (Cervus elaphus nannodes) stag roaring / rutting, an endemic subspecies to California. Point Reyes National Seashore, California.

John Cancalosi / Tourist watching Elk (Cervus canadensis) Yellowstone National park, Wyoming, USA