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

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.

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 18 days development, the tadpoles are fully developed and ready to hatch, Ecuador. Endangered.

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 11 days development, showing beating heart and blood flowing over gills, Ecuador. Endangered.

Morley Read / Rio Faisanes stubfoot toad (Atelopus coynei), Carchi Province, Ecuador, 2017. Critically endangered.

Gerry Ellis / Chimpanzee (Pan troglodytes) orphan Larry playing in tree, Ape Action Africa, Mefou Primate Sanctuary, Cameroon

Gerry Ellis / Chimpanzee (Pan troglodytes) orphans, Larry investigating Daphne's tongue, Ape Action Africa, Mefou Primate Sanctuary, Cameroon

Gerry Ellis / Chimpanzee (Pan troglodytes) orphan Larry, Ape Action Africa, Mefou Primate Sanctuary, Cameroon

Gerry Ellis / Chimpanzee (Pan troglodytes) orphan Larry playing in forest nursery, Ape Action Africa, Mefou Primate Sanctuary, Cameroon

Gerry Ellis / Chimpanzee (Pan troglodytes) orphan Larry scratching, Ape Action Africa, Mefou Primate Sanctuary, Cameroon

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

Anup Shah / Eastern Chimpanzee (Pan troglodytes schweinfurthii) fourteen year old sub-adult male, named Fundi, making submissive facial gesture, Gombe National Park, Tanzania

Anup Shah / Eastern Chimpanzee (Pan troglodytes schweinfurthii) forty-three year old female, named Gremlin, scratching face, Gombe National Park, Tanzania

Anup Shah / Eastern Chimpanzee (Pan troglodytes schweinfurthii) twenty-five year old female, named Nasa, Gombe National Park, Tanzania

Anup Shah / Eastern Chimpanzee (Pan troglodytes schweinfurthii) four year old infant male, named Gizmo, foraging for insects in log, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) twenty year old male, named Titan, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) seven year old juvenile male, named Siri, feeding on vines, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) twenty-five year old female, named Tanga, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) four year old infant male, named Gizmo, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) eighteen year old male, named Sampson, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) four year old infant male, named Gizmo, Gombe National Park, Tanzania

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Sergio Hanquet / Green sea turtle (Chelonia mydas), two viewed from above. Tenerife, Canary Islands.

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 / 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 / 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.

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

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

Ann & Steve Toon / African elephants (Loxodonta africana) herd silhouetted at sunset. Chobe National Park, Botswana.

Tony Wu / Humphead parrotfish (Bolbometopon muricatum) shoal spawning in early morning, part of mass aggregation of thousands of fish. Caroline Islands, Palau.

Will Burrard-Lucas / White rhino (Ceratotherium simum), portrait. Solio Game Reserve, Solio Ranch, Kenya. Taken with remote camera buggy / BeetleCam. EDITORIAL USE ONLY. All other uses require clearance

Sergio Hanquet / Loggerhead turtle (Caretta caretta) tangled in fishing net. Tenerife, Canary Islands. 2019.

Alex Mustard / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) swimming over Seagrass (Halophila stipulacea) meadow. Marsa Nabaa, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) feeding on Seagrass (Halophila stipulacea), blowing sand out of nostrils, on sea floor. Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Clay Bolt / Wallace's giant bee (Megachile pluto) and nest on tree trunk. North Moluccas, Indonesia.T his is the only photo that is known to exist of this species (the world's largest bee) in the wild, in situ, a...

Claudio Contreras / California condor (Gymnogyps californianus), portrait. California condor recovery program, Sierra de San Pedro Martir National Park, Baja California Peninsula, Mexico.

Claudio Contreras / California condor (Gymnogyps californianus), two perched in tree, adult and juvenile. California condor recovery program, Sierra de San Pedro Martir National Park, Baja California Peninsula, Mexico.

Tony Wu / Sperm whale (Physeter macrocephalus), ten swimming together in gathering of more than 50 individuals. Whales with flatulence and defecating. Sri Lanka.

Fabio Pupin / Meadow viper, (Vipera ursinii), basking in alpine meadow, Apennines, Italy, September . Non-ex.

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

Shane Gross / American crocodile (Crocodylus acutus) with open mouth amongst Seagrass (Alismatales). Gardens of the Queen National Park, Cuba.

Yashpal Rathore / Small tree frog (Rhacophorus lateralis) at night under starry sky, Western Ghats. India. Endangered and endemic to Western Ghats.

Gary Bell/ Oceanwide / Green Sea Turtle (Chelonia mydas), Heron Island, Great Barrier Reef, Queensland, Australia

Gary Bell/ Oceanwide / Green Sea Turtle (Chelonia mydas), Heron Island, Great Barrier Reef, Queensland, 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), 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

Gary Bell/ Oceanwide / Painted Sweetlips (Diagramma pictum) in Slender Cardinalfish (Rhabdamia gracilis) school near Double-headed Maori Wrasse (Cheilinus undulatus), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Double-headed Maori Wrasse (Cheilinus undulatus), Painted Sweetlips (Diagramma pictum), and Slender Cardinalfish (Rhabdamia gracilis) school, Great Barrier Reef, Queensland, Australia

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

Tony Heald / Elephant (Loxodonta africana) calves playing, Etosha National Park,Namibia.

Staffan Widstrand / African bush elephant, (Loxodonta africana) two head to head playing, Zimanga Private Nature Reserve, KwaZulu Natal, South Africa

Staffan Widstrand / RF - African bush elephant, (Loxodonta africana) at night, reflected in waterhole, South Africa

Bernard Castelein / Silky sifaka (Propithecus candidus) in tree, Marojejy National Park, Madagascar. Critically endagered species.

Heather Angel / Northern white cheeked gibbon (Nomascus leucogenys) female standing in tree with baby aged two weeks. Parents captive bred and released. Wild Elephant Valley / Xishuangbanna, Yunnan Province, China, 2...

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

Doug Perrine / Dugong or Sea cow (Dugong dugon) split level view, Calauit Island, off Busuanga, Calamian Islands, Palawan, Philippines.

Jordi Chias / Wandering albatross (Diomedea exulans) flying on the open ocean, Drake passage, Antarctic Peninsula, Antarctica.