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

Ismaele Tortella / Eurasian otter (Lutra lutra) hunting in a shoal of Atlantic herring (Clupea harengus), northern Norway, March

Andy Rouse / African lion (Panthera leo) female carrying young cub, Masai Mara, Kenya, Africa. Highly commended in the African Wildlife Category of the Nature's Best Photography Competition 2019.

Diane McAllister / Polar bears (Ursus maritimus) fighting in water. Beaufort Sea , Kaktovik Alaska. USA. Highly commended in the Polar Passion category of the Nature's Best Photography Competition 2019.

Claudio Contreras / Californian sea lion (Zalophus californianus) swimming in Southern sea palm (Eisenia arborea) and Giant Kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphe...

Chase Dekker / African Lion (Panthera leo) male, Masai Mara, Kenya

Chase Dekker / African Lion (Panthera leo) cub, Masai Mara, Kenya

Ann & Steve Toon / RF - Lion (Panthera leo) head portrait at night, Zimanga private game reserve, KwaZulu-Natal, South Africa. (This image may be licensed either as rights managed or royalty free.)

Jami Tarris / Polar Bear (Ursus maritimus) cooling off, Spitsbergen, Svalbard, Norway

Jami Tarris / Walrus (Odobenus rosmarus) bull, Spitsbergen, Svalbard, Norway

Jami Tarris / Polar Bear (Ursus maritimus) hunting Bearded Seal (Erignathus barbatus) pup, Spitsbergen, Svalbard, Norway

Jami Tarris / Polar Bear (Ursus maritimus) on ice floe, Spitsbergen, Svalbard, Norway

Jami Tarris / Polar Bear (Ursus maritimus) on shore, Spitsbergen, Svalbard, Norway

Jami Tarris / Arctic Fox (Alopex lagopus) running in snow, Spitsbergen, Svalbard, Norway

Juergen & Christine Sohns / African Lion (Panthera leo) six week old cubs, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / African Lion (Panthera leo) six week old cub, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / African Lion (Panthera leo) male drinking at waterhole, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / African Lion (Panthera leo) male, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / African Lion (Panthera leo) juvenile male, Mountain Zebra National Park, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pregnant female and juveniles on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pregnant female and juveniles on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) scratching itself, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / African Wild Dog (Lycaon pictus) group attacking Cape Warthog (Phacochoerus aethiopicus), Tswalu Game Reserve, South Africa

Heike Odermatt / Walrus (Odobenus rosmarus), Hinlopen Strait, Svalbard, Norway

Heike Odermatt / Walrus (Odobenus rosmarus), Svalbard, Norway

Heike Odermatt / Walrus (Odobenus rosmarus) on ice floe, Hinlopen Strait, Svalbard, Norway

Heike Odermatt / Walrus (Odobenus rosmarus) on ice floe, Hinlopen Strait, Svalbard, Norway

Heike Odermatt / Walrus (Odobenus rosmarus) on ice floe, Svalbard, Norway

Heike Odermatt / Walrus (Odobenus rosmarus) climbing on ice floe, Svalbard, Norway

Heike Odermatt / Bearded Seal (Erignathus barbatus) on ice floe, Magdalenefjorden, Svalbard, Norway

Danny Green / Polar bear (Ursus maritimus) walking across sea ice, reflected in water. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) female resting with cubs on glacier. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) female and cubs feeding on Whale carcass. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and two cubs feeding on Whale carcass. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs, standing on sea ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs resting on sea ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) female and cubs, one cub walking up slope of ice in foreground. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs feeding on Whale carcass. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs feeding on Whale carcass, on iceberg. Svalbard, Norway, July 2018.

Danny Green / Polar bear (Ursus maritimus) walking across ice, snow covered mountain in background. Svalbard, Norway, April 2018.

Danny Green / Polar bear (Ursus maritimus) resting in snow. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) licking paw, close-up. Svalbard, Norway, April.

Danny Green / Polar bear (Ursus maritimus) standing on glacier. Svalbard, Norway, July 2018.

Danny Green / Polar bear (Ursus maritimus) standing on ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) looking for food on ice. Svalbard, Norway, April.

Danny Green / Polar bear (Ursus maritimus) male standing beside rocks in frozen and snow covered landscape. Svalbard, Norway, April 2019.

Danny Green / Polar bear (Ursus maritimus) male walking across frozen landscape. Svalbard, Norway, April 2019.

Danny Green / Polar bear (Ursus maritimus) male in snow. Svalbard, Norway, April.

Danny Green / Polar bear (Ursus maritimus), male and female approaching each other across snow covered rocky landscape. Svalbard, Norway, April 2019.

Danny Green / Polar bear (Ursus maritimus) male approaching female on snow covered hill top. Svalbard, Norway, April 2019.

Danny Green / Polar bear (Ursus maritimus) male approaching female in rocky area covered in snow. Svalbard, Norway, April 2019.

Danny Green / Arctic fox (Vulpes lagopus), two in snow covered landscape. Svalbard, Norway, April 2019.

Danny Green / RF - Polar bear (Ursus maritimus) male walking through snow covered landscape, mountains in background. Svalbard, Norway, April (This image may be licensed either as rights managed or royalty free.)

Danny Green / RF - Polar bear (Ursus maritimus) cub walking in snow. Svalbard, Norway, April. (This image may be licensed either as rights managed or royalty free.)

Danny Green / RF - Polar bear (Ursus maritimus) female walking across ice. Svalbard, Norway, April. (This image may be licensed either as rights managed or royalty free.)

Danny Green / Ringed seal (Pusa hispida) and pup resting on ice. Svalbard, Norway. April.

Danny Green / Polar bear (Ursus maritimus) female and cubs play fighting. Svalbard, Norway, March 2018.

Danny Green / Polar bear (Ursus maritimus) two walking in snowy landscape. Svalbard, Norway, April 2018.

Danny Green / Polar bear (Ursus maritimus) male female pair looking upwards, snow covered hills in background. Svalbard, Norway, April 2018.

Danny Green / Polar bear (Ursus maritimus) group on ice, female and cubs feeding on Whale carcass. Svalbard, Norway, June 2018.

Danny Green / Polar bear (Ursus maritimus) resting on sea ice, view from above. Svalbard, Norway, June 2018.

Danny Green / Polar bear (Ursus maritimus) sleeping in snow. Churchill, Manitoba, Canada, November.

Danny Green / Polar bear (Ursus maritimus) hunting Seal on sea ice. Svalbard, Norway, July 2018.

Danny Green / Polar bear (Ursus maritimus), two cubs playing, leaping across sea ice, reflected in water. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus), two cubs walking on sea ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) cub ready to jump down from pack ice. Svalbard, Norway, April.

Danny Green / Ringed seal (Pusa hispida) resting on ice, reflected in water. Svalbard, Norway. July.

Nick Garbutt / Puma (Puma concolor puma) young male standing with mouth open. Estancia Amarga, near Torres del Paine National Park, Patagonia, Chile. December.

Nick Garbutt / Western red panda (Ailurus fulgens fulgens) climbing in tree. Singalila National Park, India / Nepal border.

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.)

Ann & Steve Toon / Cheetah (Acinonyx jubatus) walking, silhouetted at dusk. Zimanga private game reserve, KwaZulu-Natal, South Africa.

Felis Images / Asiatic lion (Panthera leo persica), female and cubs in morning light, cub biting mother's leg. Gir National Park, Gujarat, India. Photo Phillip Ross/Felis Images

David Tipling / Grey seal (Halichoerus grypus) female in surf, Horsey, Norfolk, England, UK, February.

David Tipling / Grey seal (Halichoerus grypus) pup, Horsey, Norfolk, England, UK, February.

Ann & Steve Toon / Meerkats (Suricata suricatta) on the move, Kgalagadi Transfrontier Park, Northern Cape, South Africa, January. Second place in the Mammals Category of the GDT European Nature Photographer of the Year...

Andy Rouse / Bengal tiger (Panthera tigris) male, sub-adult aged three years, face portrait. Ranthambhore National Park, India.

Gary Bell/ Oceanwide / Australian Sea Lion (Neophoca cinerea), Hopkins Island, South Australia, Australia

Gary Bell/ Oceanwide / Australian Sea Lion (Neophoca cinerea), Hopkins Island, South Australia, Australia

Gary Bell/ Oceanwide / Australian Sea Lion (Neophoca cinerea), Hopkins Island, South Australia, Australia

Gary Bell/ Oceanwide / Australian Sea Lion (Neophoca cinerea) group, Hopkins Island, South Australia, Australia

Gary Bell/ Oceanwide / Australian Sea Lion (Neophoca cinerea) group, Hopkins Island, South Australia, Australia

Tony Heald / African wild dog (Lycaon pictus) portrait. Chobe National Park Botswana. Digitally enhanced sepia image.

Heather Angel / Giant panda (Ailuropoda melanoleuca) portrait, in falling snow. Captive bred, in enclosure, Panda Breeding Centre, Wolong, Sichuan Province, China. February 2008.

Andy Rouse / Bengal Tiger (Panthera tigris) family drinking from pool, Ranthambhore, India

Jordi Chias / Crabeater seals (Lobodon carcinophaga) resting on ice floating ice sheet, Antarctic Peninsula, Antarctica.

Jordi Chias / Antarctic fur seal (Arctocephalus gazella), Antarctic Peninsula, Antarctica.

Jordi Chias / Antarctic fur seal (Arctocephalus gazella), Antarctic Peninsula, Antarctica.

Jordi Chias / Crabeater seals (Lobodon carcinophaga), Antarctic Peninsula, Antarctica.

Jordi Chias / Leopard seal (Hydrurga leptonyx) with mouth open, Antarctic Peninsula, Antarctica.