Heather Angel / Giant panda (Ailuropoda melanoleuca) sliding down slope on back after losing footing. Panda Breeding Centre, Wolong, Sichuan, China. January 1987.

Chadden Hunter / Canadian timber wolf / Northwestern wolf (Canis lupus occidentalis) pack moving through snow, Wood Buffalo National Park, Alberta, Canada. Taken on location for BBC Frozen Planet, March 2009.

John Shaw / Grey wolf in snow (Canis lupus), Minnesota, USA. January. Controlled situation.

John Shaw / Grey wolves running in snow (Canis lupus), Minnesota, USA. January. Controlled situation.

Danny Green / Willow Tit (Poecile montanus) on a snowy branch. Utsjoki, Finland, February.

Danny Green / Whooper Swans (Cygnus cygnus) in snow. Japan, February.

Danny Green / Waxwings (Bombycilla garrulus), in snow. Finland, March

Danny Green / Roe Deer (Capreolus capreolus) in snow. Flatanger, Norway, January.

Danny Green / Mountain hare (Lepus timidus) resting Cairngorms, Scotland, March

Erlend Haarberg / Moose (Alces alces), calves near house in winter, Jokkmokk, Sweden, February.

Erlend Haarberg / Scots pine (Pinus sylvestris), in coastal landscape, Efjorden, Nordland, Norway, February.

Erlend Haarberg / Red fox (Vulpes vulpes), on spring snow, Vauldalen, Norway, April.

Erlend Haarberg / Common reeds (Phragmites australis) on a frozen lake, Sel, Norway, March.

Erlend Haarberg / Arctic fox (Vulpes lagopus), Dovrefjell-Sunndalsfjella National Park, Norway, April.

Erlend Haarberg / Svalbard reindeer (Rangifer tarandus platyrhynchus), Svalbard, Norway, September.

Erlend Haarberg / Rock ptarmigan (Lagopus muta) in flight, Tysfjorden, Nordland, Norway, March.

Erlend Haarberg / Mountain hare (Lepus timidus) in spring outside a Norwegian house, Vauldalen, Norway, May.

Erlend Haarberg / Mountain hare (Lepus timidus) in spring, Vauldalen, Norway, May.

Erlend Haarberg / Muskox (Ovibus moschatos) males, Dovrefjell-Sunndalsfjella National Park, Norway, February.

Guy Edwardes / Red-crowned crane (Grus japonensis) courtship dance in snow, Hokkaido, Japan

Guy Edwardes / Dalmatian pelicans (Pelecanus crispus) on ice, Lake Kerkini, Greece

Guy Edwardes / Hawfinch (Coccothraustes coccothraustes) fighting in snow, Bulgaria

Markus Varesvuo / Hazel Grouse (Tetrastes bonasia), Kuusamo, Finland, December.

Markus Varesvuo / Hawk Owl (Surnia ulula) hunting, Kuhmo, Finland, March.

Markus Varesvuo / Great Grey Owl (Strix nebulosa) Kuhmo Finland, March.

Markus Varesvuo / Great Grey Owl (Strix nebulosa) hunting over snow, Kuhmo Finland, March.

Markus Varesvuo / Golden eagle (Aquila chrysaetus), Kuusamo, Finland, January.

Markus Varesvuo / Golden eagle (Aquila chrysaetus) landing in snow, Kuusamo, Finland, December..

Markus Varesvuo / Bullfinch (Pyrrhula pyrrhula) in flight, Kuusamo, Finland, March.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) two adults brooding chicks age 5 weeks, Antarctica. Highly commended in the Polar Passion Category of the Nature's Best Photography Awards 2019.

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

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

Ismaele Tortella / Three Rock ptarmigan (Lagopus muta) feeding in winter plumage, city of Tromso in the background, northern Norway, March 2019.

Ismaele Tortella / Aerial tracking shot over Tromso in the winter, northern Norway, March 2019.

Andres M. Dominguez / Siberian tit (Poecile cinctus) perched, Ivalo, Finland. March

Andres M. Dominguez / Pine grosbeak (Pinicola enucleator) Ivalo, Finland. March

Andres M. Dominguez / Guillemots (Uria aalge) in flight over snow, Vardo, Norway, March.

Andres M. Dominguez / Guillemots (Uria aalge) in flight over snow, Vardo, Norway, March.

Andres M. Dominguez / Riisitunturi in winter with Aurora Borealis, Kuusamo, Lapland, Finland. February

Nick Garbutt / RF - Red fox (Vulpes vulpes) foraging in snow covered valley. Hayden Valley, Yellowstone National Park, USA. February 2019. (This image may be licensed either as rights managed or royalty free.)

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

Nick Garbutt / Black-browed albatross (Thalassarche melanophris) flying over South Atlantic. Cooper Bay, South Georgia. November.

Nick Garbutt / King penguin (Aptenodytes patagonicus), two sleeping on snow. Grytviken, South Georgia. March.

Danny Green / Arctic fox (Alopex lagopus) in snow. Svalbard, Norway. April.

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.