Ismaele Tortella / Four Eurasian elk (Alces alces) walking through vegetation , Norway, August

Ismaele Tortella / Svalbard reindeer (Rangifer tarandus platyrhynchus) feeding in snow, Svalbard, Norway, March.

Ismaele Tortella / Reindeer (Rangifer tarandus), Kvaloya island, Tromso, Norway, November.

Danny Green / RF - Reindeer (Rangifer tarandus) walking up slope in snow. Svalbard, Norway, April. (This image may be licensed either as rights managed or royalty free.)

Danny Green / Reindeer (Rangifer tarandus), two standing on ridge in blizzard. Svalbard, Norway. April.

Danny Green / Reindeer (Rangifer tarandus), two play fighting in snow. Svalbard, Norway, April.

Danny Green / Reindeer (Rangifer tarandus), two standing on ridge in snow. Svalbard, Norway, April.

Danny Green / Reindeer (Rangifer tarandus) standing on ridge in snow, another reindeer in background. Svalbard, Norway, April.

Danny Green / Reindeer (Rangifer tarandus) hunkering down in snow during blizzard. Svalbard, Norway, April.

Danny Green / Reindeer (Rangifer tarandus) walking in snow. Svalbard, Norway, April.

Nick Garbutt / American bison (Bison bison) female covered in hoar frost near hot spring, portrait. Midway Geyser Basin, Yellowstone National Park, USA. February.

Oscar Dewhurst / Fallow deer (Dama dama) walking across frost-covered playing fields at dawn, with tower blocks of London in the background. Richmond Park, London, UK. December

Oscar Dewhurst / Red deer (Cervus elaphus) stag roaring, silhouetted under trees at sunrise. Bushy Park, London, UK. September

Jack Dykinga / Bighorm sheep (Ovis canadensis) males grouped together before the rutting season. Valley of Fire State Park, Nevada, USA, February.

David Woodfall / Red Deer (Cervus elaphus) portrait of head of stag and antlers. Alladale Estate, Scotland, UK, October.

David Woodfall / Red deer (Cervus elaphus) on moorland / blanket bog silhouetted against rushes, Alladale Estate, Scotland, UK, October.

Yashpal Rathore / Bengal tiger (Panthera tigris tigris) tigress (T32) feeding on Spotted deer / Chital (Axis axis) killed by her earlier that day while her young cub watches. Kanha National Park, Central India. Camera...

SCOTLAND: The Big Picture / Red deer, (Cervus elaphus), stag silhouetted at sunset, Scotland, UK.February

SCOTLAND: The Big Picture / Red deer, (Cervus elaphus), stags silhouetted at sunset in winter, Scotland, UK.February

SCOTLAND: The Big Picture / Red deer, (Cervus elaphus), stags silhouetted at sunset in winter, Scotland, UK.February

SCOTLAND: The Big Picture / Red deer, (Cervus elaphus), stag in rough grassland, Jura, Scotland, UK., April

David Pattyn / Alpine ibex (Capra ibex) adult males fighting in alpine landscape, Valsavarenche, Gran Paradiso National Park, Aosta Valley, Italy, May

David Pattyn / Alpine Ibex (Capra ibex) in its landscape, Valsavarenche, Gran Paradiso national park, Aosta Valley, Italy, May

David Pattyn / Alpine ibex (Capra ibex) struggling in deep snow on a steep slope, Valsavarenche, Gran Paradiso National Park, Aosta Valley, Italy, January

Eric Baccega / Female Uganda kob (Kobus kob thomasi) suckling calf. Murchisson Falls National Park, Uganda. February.

Jed Weingarten / Wild Wonders of China / Takin (Budorcas taxicolor) Tangjiahe Nature Reserve, Sichuan Province, China. April.

Jed Weingarten / Wild Wonders of China / White-lipped deer (Cervus albirostris) stags in mountain landscape, Serxu County, Garze Prefecture, Sichuan Province, China.

Jed Weingarten / Wild Wonders of China / Snow leopard (Uncia uncia) with Bharal (Pseudois nayaur) prey, Serxu County, Garze Prefecture, Sichuan Province, China.

Jed Weingarten / Wild Wonders of China / White-lipped deer (Cervus albirostris) male, Serxu, Garze Prefecture, Sichuan Province, China

Jed Weingarten / Wild Wonders of China / Injured Muntjac (Muntiacus reevesi) swimming in a small creek after unsuccessfully attempting to jump across it. This muntjac was unable to get out of the creek himself, and was later rescued by the p...

Staffan Widstrand / Wild Wonders of China / Pere David's deer / Milu (Elaphurus davidianus) male walking in the morning,Hubei Tian'ezhou Milu National Nature Reserve, Shishou, Hubei, China

Staffan Widstrand / Wild Wonders of China / Pere David's deer / Milu (Elaphurus davidianus) stag, walking in the morning in Hubei Tian'ezhou Milu National Nature Reserve, Shishou, Hubei, China

Staffan Widstrand / Wild Wonders of China / Pere David's deer / Milu (Elaphurus davidianus), two stags testing their strength in Hubei Tian'ezhou Milu National Nature Reserve, Shishou, Hubei, China

Staffan Widstrand / Wild Wonders of China / Pere David's deer / Milu (Elaphurus davidianus), walking through water of Yangtze river, Hubei Tian'ezhou Milu National Nature Reserve, Shishou, Hubei, China

Staffan Widstrand / Wild Wonders of China / Pere David's deer / Milu (Elaphurus davidianus) stag wading through the water of the Yangtze river, Hubei Tian'ezhou Milu National Nature Reserve, Hubei, China

Sven Zacek / Roe deer (Capreolus capreolus) young buck, portrait. Karula National Park, Valgamaa, Southern Estonia. June.

Anup Shah / Mixed herd of Common or Plains zebra (Equus quagga burchellii) and Eastern white-bearded wildebeest (Connochaetes taurinus) - remote camera. Masai Mara National Reserve, Kenya.

Guy Edwardes / Misty landscape with Red deer (Cervus elaphus) Black Mount, Highlands, Scotland, November.

Paul Hobson / Red deer (Cervus elaphus) herd during rut in morning light. Derbyshire, England, UK. October.

Paul Hobson / Red deer (Cervus elaphus) stags in snowy Pine forest. Scotland, UK. March.

SCOTLAND: The Big Picture / Red deer (Cervus elaphus) stag in upland landscape. Lochcarron, Highlands, Scotland, UK.

SCOTLAND: The Big Picture / Red deer (Cervus elaphus) stag in upland landscape. Lochcarron, Highlands, Scotland, UK.

Ann & Steve Toon / Impala (Aepyceros melampus) allo-grooming, iMfolozi game reserve, KwaZulu-Natal, South Africa, August

Loic Poidevin / Alpine ibex (Capra ibex) female, Jura, Switzerland, September.

Axel Gomille / Red deer (Cervus elaphus) stag, Saxony, Germany. September.

Erlend Haarberg / Semi-domesticated reindeer (Rangifer tarandus) walking on snow-covered road in pine forest. Lapland, Sweden. February.

Erlend Haarberg / Herd of wild Reindeer (Rangifer tarandus) in snow-covered mountain landscape, in wind storm. Forollhogna, Norway. January 2018.

Nick Garbutt / Male American Bison (Bison bison) walking through snow. Firehole River Valley, Yellowstone National Park, Wyoming, USA. January

Paul Williams / Moose (Alces alces) female with twin calves, Baxter State Park, Maine, USA, June.

Philippe Clement / Pair of Roe deer (Capreolus capreolus) resting and grazing in forest in summer, France, September.

Sandesh Kadur / Blue wildebeest (Connochaetes taurinus) crossing a river, Serengeti National Park, Tanzania.

Stephane Granzotto / Alpine ibex (Capra ibex) feeding in deep snow, digging to reach food, Rhone-Alpes, France, December.

Staffan Widstrand / Wild Wonders of China / Sichuan / Tibetan takin (Budorcas taxicolor tibetana) walking through a forest in Tangjiahe National Nature Reserve,Qingchuan County, Sichuan province, China

Valeriy Maleev / Siberian musk deer (Moschus moschiferus) male, Irkutsk, Russia. March.

Ann & Steve Toon / Springbok (Antidorcas marsupialis) herd fleeing predator, Kgalagadi Transfrontier Park, South Africa.

Guy Edwardes / Red-billed oxpecker (Buphagus erythrorhynchus) feeding on Impala (Aepyceros melampus), Savuti, Botswana.

Jim Manthorpe / American bison (Bison bison) feeding, Yellowstone National Park, Wyoming, USA, August.

Nick Garbutt / Urial sheep (Ovis vignei) herd running across steep barren slopes. Himalayas near Ulley, Ladakh, India.

Philippe Clement / Red deer (Cervus elaphus) stags fighting, Scotland, UK, May.

Claudio Contreras / Young girl face to face with Peninsular Pronghorn Antelope (Antilocapra americana peninsularis) fawn at Peninsular Pronghorn recovery project, El Vizcaino Desert Biosphere Reserve, Baja California Pen...

Bence Mate / African buffalo (Syncerus caffer) at waterhole at night, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Bence Mate / Fallow deer (Dama dama) at night, Gyulaj, Hungary Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Bence Mate / Fallow deer (Dama dama) at night, Gyulaj, Hungary Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Bence Mate / African buffalo (Syncerus caffer) and Warthog (Phacochoerus africanus) at night with full moon, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Bence Mate / African buffalo (Syncerus caffer) at waterhole at night, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Ann & Steve Toon / Impala (Aepyceros melampus) with redbilled oxpecker (Buphagus erythrorhynchus), Kruger National Park, South Africa.

Philippe Clement / Lynx (Lynx lynx) feeding on a Roe deer (Capreolus capreolus) in snow in winter, with juvenile passing by, Bavarian Forest National Park, Germany, January. Captive.

Francisco Marquez / Two male Iberian wild goats (Capra pyrenaica) fighting, Sierra de Gredos, Spain, November.

Ingo Arndt / Svalbard reindeers (Rangifer tarandus platyrhynchus) running in snow, winter, Spitsbergen, Svalbard, Norway, April

Philippe Clement / Group of Alpine ibex (Capra ibex) climbing a cliff face, with others fighting above them, Gran Paradiso National Park, Graian Alps, Italy, June.

Philippe Clement / Three male Alpine ibex (Capra ibex) climbing up a steep mountain rock face, one pushes another one away, Gran Paradiso National Park, Graian Alps, Italy, June.

Philippe Clement / Two male Alpine ibex (Capra ibex) fighting on a steep mountain rock face, Gran Paradiso National Park, Graian Alps, Italy, June.

SCOTLAND: The Big Picture / A large herd of Red deer (Cervus elaphus) on a hillside in the snow, Cairngorms National Park, Scotland, UK, January.

SCOTLAND: The Big Picture / A large herd of Red deer (Cervus elaphus) on a hillside in the snow, Cairngorms National Park, Scotland, UK, January.

SCOTLAND: The Big Picture / A large herd of Red deer (Cervus elaphus) on a hillside in the snow, Cairngorms National Park, Scotland, UK, January.

Pal Hermansen / Herd of domesticated Reindeer (Rangifer tarandus) moving around, Norway, September.

Pal Hermansen / Herd of domesticated Reindeer (Rangifer tarandus) moving around, Norway, September.

Eric Baccega / Small herd of Muskox (Ovibos moschatus) feeding in a blizzard, Banks Island, Northwest Territories, Canada.

Danny Green / Bison (Bison bison) herd walking in line in snow, Yellowstone National Park, Wyoming, USA, February

Inaki Relanzon / Arabian Oryx (Oryx leucoryx) at sunset. Previously extinct in the wild, their conservation status is now stable thanks to conservation efforts.This male is part of a reintroduction program in Dubai, U...

Ann & Steve Toon / Common wildebeest (Connochaetes taurinus) with reflection at waterhole, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Ann & Steve Toon / Sable (Hippotragus niger), Chobe National Park, Botswana, June

Ann & Steve Toon / Cape buffalo (Syncerus caffer) at waterhole at night with plains zebra (Equus quagga), Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Ann & Steve Toon / Cape buffalo (Syncerus caffer) drinking at waterhole at night, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Ann & Steve Toon / Cape buffalo (Syncerus caffer) drinking at waterhole at night, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Nick Garbutt / Herd of American bison (Bison bison) in snow, Yellowstone National Park, Wyoming, Yellowstone, January.

Denis-Huot / Blue wildebeest (Connochaetes taurinus), migrating herd silhouetted on the horizon at sunset, Masai Mara Game Reserve, Kenya

David Pattyn / Chamois (Rupicapra rupicapra) in deep snow, Gran Paradiso National Park, Italy. November. Commended in the Asferico Photography Competition 2016.

Sergey Gorshkov / Lionesses (Panthera leo) trying to bring down African buffalo (Syncerus caffer) Londolozi Private Game Reserve, Sabi Sands Game Reserve, South Africa. Sequence 1 of 5

Sergey Gorshkov / Lionesses (Panthera leo) trying to bring down African buffalo (Syncerus caffer) Londolozi Private Game Reserve, Sabi Sands Game Reserve, South Africa. Sequence 2 of 5

Sergey Gorshkov / Lionesses (Panthera leo) trying to bring down African buffalo (Syncerus caffer) Londolozi Private Game Reserve, Sabi Sands Game Reserve, South Africa. Sequence 3 of 5

Sergey Gorshkov / Lioness (Panthera leo) trying to bring down African buffalo (Syncerus caffer) Londolozi Private Game Reserve, Sabi Sands Game Reserve, South Africa. Sequence 4 of 5