Bence Mate / Portrait of Roe deer buck (Capreolus capreolus) in woodland, Pusztaszer, Kiskunsagi National Park, Hungary

Erlend Haarberg / Wild Reindeer (Rangifer tarandus) silhouetted, Forollhogna National Park, Sor-Trondelag, Norway, September

Erlend Haarberg / Muskoxen (Ovibos moschatus) head portrait, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, December

Bernard Castelein / Hog Deer (Cervus / Axis / Hyelaphus porcinus) crossing a stream. Kaziranga National Park, Assam, India, February.

David Woodfall / Bengal tiger (Panthera tigris tigris) stalking a herd of Chital deer using long grass as cover, Bandhavagah NP, Madhya Pradesh, India

Bernard Castelein / Barasingha / Swamp Deer (Cervus duvauceli), females, Kaziranga NP, Assam, India, vulnerable species

Juergen Freund / Bornean bearded pigs (Sus barbatus) mother and young, foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) foraging, Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) mother and young, foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) mother and young, foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Juergen Freund / Bornean bearded pigs (Sus barbatus) foraging on Teluk Assam Beach. Bako National Park, Sarawak, Borneo, Malaysia

Bernard Castelein / Herd of Wild Gaur (Bos gaurus). Trishna wildlife sanctuary, Tripura, India.

Erlend Haarberg / Two Muskoxen (Ovibos moschatus) standing head to head, Dovrefjell-Sunndalsfjella National Park, Norway, December

Erlend Haarberg / Muskox (Ovibos moschatus) herd grazing in snow, Dovrefjell-Sunndalsfjella National Park, Norway, December 2011

Erlend Haarberg / Red deer (Cervus elaphus) pair mating, another female nearby feeding, Danube-Drava National Park, Hungary, November

Erlend Haarberg / Four Muskoxen (Ovibos moschatus) lying covered in snow after snowstorm, Dovrefjell-Sunndalsfjella National Park, Norway, March

Erlend Haarberg / Muskox (Ovibos moschatus) lying covered in snow after snowstorm, Dovrefjell-Sunndalsfjella National Park, Norway, March

Erlend Haarberg / Muskox (Ovibos moschatus) lying covered in snow, Dovrefjell-Sunndalsfjella National Park, Norway, March

Erlend Haarberg / Muskox (Ovibos moschatus) herd covered in snow, Dovrefjell-Sunndalsfjella National Park, Norway, March

Erlend Haarberg / Muskox (Ovibos moschatus) herd in snow, Dovrefjell-Sunndalsfjella National Park, Norway, March

Erlend Haarberg / Wild Reindeer (Rangifer tarandus) herd in snow, Forollhogna National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Wild Reindeer (Rangifer tarandus) herd in snow, Forollhogna National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Wild Reindeer (Rangifer tarandus) herd in snow, Forollhogna National Park, Sr-Trndelag, Norway, January

Erlend Haarberg / Wild Reindeer (Rangifer tarandus) herd in snow, Forollhogna National Park, Sor-Trondelag, Norway, January

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

Erlend Haarberg / Bull European elk / Moose (Alces alces) walking, Sarek National Park, Sweden, September

Erlend Haarberg / Female European elk / Moose (Alces alces) with head raised in air, Sarek National Park, Sweden, September

Erlend Haarberg / Muskox (Ovibos moschatus) herd, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Muskoxen (Ovibos moschatus) walking with snow stuck to fur, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Muskox (Ovibos moschatus) lying down rear view, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Two Muskoxen (Ovibos moschatus) others grazing in background, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, January

Erlend Haarberg / Muskoxen (Ovibos moschatus) grazing in snow, Dovrefjell-Sunndalsfjella National Park, Sor-Trondelag, Norway, December

John Cancalosi / Two White-tailed Deer (Odocoileus virginianus) does looking nervously at camera. New York State, USA.

Grzegorz Lesniewski / Carpathian forest stream in autumn colors. Bieszczady National Park, the Carpathians, Poland, November 2009.

Bryan and Cherry Alexander / Muskox (Ovibos moschatus) skull in the valley at Eleonora Bay, North-East Greenland National Park, September 2005.

Bryan and Cherry Alexander / Muskox (Ovibos moschatus) skull in the valley at Eleonora Bay, North-East Greenland National Park, September 2005.

Bernard Castelein / Hog Deer (Cervus / Axis / Hyelaphus porcinus), eating the flower of a Cotton Silk Tree (Bombax ceiba). Kaziranga National Park, Assam, India, February.

Bernard Castelein / Hog Deer (Cervus / Axis / Hyelaphus porcinus) in profile. Kaziranga National Park, Assam, India, February.

Bernard Castelein / Hog Deer (Cervus / Axis / Hyelaphus porcinus) juvenile. Kaziranga National Park, India, February.

Juan Carlos Munoz / Muskox (Ovibos moschatus) walking across the tundra in autumn, Dovrefjell NP, Norway, September 2008

Richard Du Toit / Hippopotamus (Hippopotamus amphibius) male with Oxpecker on its back, Chobe NP, Botswana, July

David Woodfall / Young male Sunda sambar deer (Cervus timorensis) in velvet, Bandhavgah NP, Madhya Pradesh, India, November

David Woodfall / Sunda sambar deer (Cervus timorensis ) young male in velvet browsing on bush, Bandhavgah NP, Madhya Pradesh, India

David Woodfall / Sunda Sambar deer (Cervus timorensis) young male in velvet feeding on bush, Bandhavgah NP, Madhya Pradesh, India

David Woodfall / Female Sunda sambar deer (Cervis timorensis ) amongsts reeds, Bandhavgah NP, Madhya Pradesh, India, November

David Woodfall / Young male Sunda sambar deer (Cervus timorensis) amongst reeds, Bandhavgah NP, Madhya Pradesh, India

Bernard Castelein / Hog Deer (Axis / Cervus porcinus), Kaziranga NP, Assam, India, Endangered species

Bernard Castelein / Barasingha / Swamp Deer (Cervus duvauceli), female and young, Kaziranga NP, Assam, India, vulnerable species

Juan Carlos Munoz / Muskox {Ovibos moschatus} pair on the tundra in autumn, Dovrefjell National Park, Norway, September 2008

Tim Laman / Mule deer (Odocoileus hemionus) bucks in velvet, one running, one grazing, in Tuolume Meadows at Yosemite National Park, California.

Richard Du Toit / Male Steenbok (Raphicerus campestris) portrait, Kruger National Park, South Africa

Richard Du Toit / Giraffe (Giraffa camelopardalis) crossing savanna with storm clouds behind, Etosha NP, Namibia

Peter Blackwell / Group of Giraffes silhouetted at sunset (Giraffa camelopardalis) Kenya Masai Mara

Bernard Castelein / Male and female Indian sambar (Cervus unicolor) feeding in lake, Ranthambore NP, India

TJ Rich / Hippopotamus walking along track at dawn (Hippopotamus amphibius) covered with Oxpeckers, South Luangwa NP, Zambia

Peter Blackwell / Kirk's dik dik {Madoqua kirki} Masai Mara NP, Kenya

Richard Du Toit / Kirk's dik dik (Madoqua kirki) male, Etosha NP, Namibia

Bernard Castelein / Wild gaur {Bos gaurus} Kanha NP, Madhya Pradesh, India

Bernard Castelein / Male Indian sambar male (Cervus unicolor) with house crows, Ranthambore NP. Rajasthan, India

Bernard Castelein / Large herd of Bison grazing (Bison bison) in Hayden Valley, near Yellowstone River, Yellowstone NP, Wyoming, USA

Richard Du Toit / Female Giraffe suckling calf (Giraffa camelopardalis) Kruger NP,South Africa

Richard Du Toit / Male and female Giraffe (Giraffa camelopardalis) with Elephants (Loxodonta africana) at waterhole, Chobe NP, Botswana

RHONDA KLEVANSKY / Misty mountain landscape with solitary Guanaco {Lama guanicoe} Torres del Paine NP, South Chile, South America

RHONDA KLEVANSKY / Solitary Guanaco {Llama guanicoe} Torres del Paine NP, Chile, South America

Richard Du Toit / Large herd of resting Elk {Cervus elaphus} Mammoth Camp Ground, Yellowstone NP, Wyoming USA, Autumn

Richard Du Toit / Greater kudu calf portrait {Tragelaphus strepsiceros} Chobe NP, Botswana

Peter Blackwell / Hippopotamus (hippopotamus amphibius) relaxing in the mud. Masai Mara reserve, Kenya

Bernard Castelein / Chital / Spotted deer {Axis axis} hind and calf, Female drinking. India

Jose Luis GOMEZ de FRANCISCO / Golden eagle {Aquila chrysaetos} feeding on Chamois carcass, Ordesa NP, Spain