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.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) male calf playing at ocean surface after coming up to breathe. Vava'u Islands, Tonga.

Jack Dykinga / Burrowing owl (Athene cunicularia) female and ten chicks aged a few weeks. Marana, Arizona, USA. May.

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

Shane Gross / Caribbean reef shark (Carcharhinus perezi), two from below, one close up. Caribbean Sea off Gardens of the Queen National Park, Cuba.

Sven Zacek / Ural owl (Strix uralensis) perched in tree sleeping, viewed through a fence, Estonia.

Doug Gimesy / Little blue penguin (Eudyptula minor), two standing on rocks at night, silhouetted against Melbourne city lights. St Kilda breakwater, Victoria, Australia. ??December 2016.

Tony Heald / Glaucous Gull (Larus hyperboreus) taking off from ice, Svalbard Norway, July.

George Sanker / Great egret (Ardea alba) with prey in beak, in evening light. Myakka River State Park, Florida, USA, March. Sequence 2/2.

George Sanker / Great egret (Ardea alba) diving head into water to catch prey, in evening light. Myakka River State Park, Florida, USA, March. Sequence 1/2.

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

Cyril Ruoso / Ringed-tailed lemur (Lemur catta) amongst granite rocks in cave. Lemurs lick minerals from the rocks. Anja Community Reserve, Madagascar.

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

Staffan Widstrand / Southern Giraffe (Giraffa camelopardalis) two, with one in foreground, Zimanga Private Nature Reserve, KwaZulu Natal, South Africa

Staffan Widstrand / Tawny eagle (Aquila rapax) in flight, about to land, Zimanga Private Nature Reserve, KwaZulu Natal, South Africa

Sven Zacek / Ural owl (Strix uralensis) hunting, Tartumaa county, Southern Estonia.

Oscar Dewhurst / Hoatzin (Ophisthocomus hoazin) perched on wooden bar overlooking oxbow lake. Manu National Park, Madre de Dios, Peru. September

Sven Zacek / Ural owl (Strix uralensis) in flight, hunting, Tartumaa county, Southern Estonia. February.

Bernard Castelein / Coquerel's sifaka (Propithecus coquereli) in tree, relaxing, Ankarafantsika National Park, Madagascar

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

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

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

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.

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

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

Jordi Chias / Humpback whale (Megaptera novaeangliae), Antarctic Peninsula, Antarctica.

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

Jordi Chias / Leopard seal (Hydrurga leptonyx) resting over an iceberg, Antarctic Peninsula, Antarctica.

Jordi Chias / Crabeater seal (Lobodon carcinophaga) hunting under water, Antarctic Peninsula, Antarctica.

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

Jordi Chias / Gentoo penguins (Pygoscelis papua) swimming together and porpoising in search of krill, Antarctic Peninsula, Antarctica.

Jordi Chias / Gentoo penguins (Pygoscelis papua) walking in line, returning to nesting area, Port Charcot, Antarctic Peninsula, Antarctica.

Jordi Chias / Weddell seal (Leptonychotes weddellii) hauled out on ice, Antarctic Peninsula, Antarctica.

Jordi Chias / Gentoo penguins (Pygoscelis papua) walking in line, returning to nesting area, Port Charcot, Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) spyhoping, Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) surfacing with baby and blowing, Antarctic Peninsula, Antarctica.

Franco Banfi / School of Munk's devil ray, pygmy devil ray, (Mobula munkiana), feeding on plankton at night, photographed on a long exposure, Espiritu Santo Island, Sea of Cortez, Baja California, Mexico, East Pacif...

Nick Upton / Captive reared juvenile White stork (Ciconia ciconia) in flight over the Knepp Estate soon after release, Sussex, UK, August 2019.

Nick Upton / Captive reared juvenile White stork (Ciconia ciconia) with a GPS tracker on its back in flight over the Knepp Estate soon after release, Sussex, UK, August 2019.

Yashpal Rathore / Bengal tiger (Panthera tigris tigris) walking at night, with monsoon clouds and lightning. Kanha National Park, Central India. Dominant male (T29)

Alex Hyde / Colonies of King penguins (Aptenodytes patagonicus) and Southern Elephant Seals (Mirounga leonina) on beach at St. Andrews Bay, South Georgia. November.

Stephane Granzotto / Alpine marmot (Marmota marmota) standing alert outside burrow, takes fright and runs inside, Rhone-Alpes, France, July.

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

Stephane Granzotto / Tracking shot of a pod of Euphrosyne dolphins (Stenella coeruleoalba) swimming, Mediterranean Sea, August.

David Fleetham / Humpback Whale (Megaptera novaeangliae) beginning a deep dive. Hawaii.

David Fleetham / Fire Dartfish / Fire Goby (Nemateleotris magnifica) against colourful coral. Fiji's outer reef.

David Fleetham / Jaws and teeth of Stout Moray (Gymnothorax eurostus). Hawaii.

David Fleetham / Galapagos Sea Lion (Zalophus californianus wollebacki) framed by a school of Black Striped Salema (Xenocys jessiae). Santa Cruz Island, Galapagos Islands, Equador.

David Fleetham / Patterns of diffused sunlight on Humpback whale (Megaptera novaeangliae), Hawaii.

David Fleetham / Curious Humpback whale calf (Megaptera novaeangliae) during moment away from its mother, Hawaii.

David Fleetham / Schooling Lemon / Milletseed butterflyfish (Chaetodon miliaris) below kayakers off Maui, Hawaii.

David Fleetham / Lemon sharks (Negaprion brevirostris) viewed from below. West End, Grand Bahamas, Caribbean.

David Fleetham / Lemon shark (Negaprion brevirostris) viewed from below. West End, Grand Bahamas, Caribbean.

David Fleetham / Schooling Lemon butterflyfish (Chaetodon miliaris) near to surface. Maui, Hawaii.

David Fleetham / Looking upwards to schooling Lemon butterflyfish (Chaetodon miliaris) near to surface. Maui, Hawaii.

David Fleetham / Florida manatee (Trichechus manatus latirostris) at Three Sisters Spring in Crystal River, Florida, USA.

David Fleetham / Marine iguana (Amblyrhynchus cristatus) emerging from ocean into Mangroves (Rhizophoraceae). Santa Cruz Island, Galapagos, Ecuador.

David Fleetham / False killer whale (Pseudorca crassidens) just below surface exhaling as it breaks the surface. Maui, Hawaii.

David Fleetham / Tiny Whitespotted bamboo shark (Chiloscyllium plagiosum) formed inside egg casing, Philippines.

David Fleetham / Mouth of the worlds largest fish, the Whale shark (Rhincodon typus), Donsol, Philippines.

David Fleetham / Schooling Raccoon butterflyfish (Chaetodon lunula) framed in a lava formation off the island of Lanai, Hawaii.

David Fleetham / Schooling Raccoon butterflyfish (Chaetodon lunula) framed in a lava formation off the island of Lanai, Hawaii.

David Fleetham / Spinyhead blenny (Acanthemblemaria spinosa) in hard coral, Netherlands Antilles, Bonaire, Caribbean.

David Fleetham / Schooling Brown striped snapper (Xenocys jessiae) and Yellowtail sawtail (Prionurus laticlavius), Galapagos Islands, Ecuador.

David Fleetham / White mouthed moray eel (Gymnothorax meleagris), Hawaii.

David Fleetham / Pair of Yellow edged moray eels (Gymnothorax flavimarginatus) in coral crevice, Hawaii.

David Fleetham / Clown anemonefish (Amphiprion ocellaris), Philippines.

David Fleetham / White-eyed moray eel (Muraena thyrsoides) close to Zebra lionfish (Dendrochirus zebra), Philippines.

David Fleetham / Striped triplefin (Helcogramma striata) on hard coral, Tubataha Reef, Philippines.

David Fleetham / Pair of Tomato anemonefish (Amphiprion frenatus) in Bulb tenacle sea anemone (Entacmaea quadricolor), Philippines.

David Fleetham / Garibaldi (Hypsypops rubicundus) the state fish of California, in forest of giant kelp, (Macrocystis pyrifera) Catalina Island, California, USA.

David Fleetham / Sargasum frogfish (Histiro histiro) near the surface floating on discarded polypropylene rope, Hawaii.

David Fleetham / Pair of White-eyed moray eels (Muraena thyrsoides) share the hole of a mooring block off Bali, Indonesia.

David Fleetham / Goby (Eviota sp) and juvenile porcelain crab (Pteroeides sp), on a Seapen. Komodo National Park, Indonesia.

David Fleetham / Pixy hawkfish (Cirrhitichthys oxycephalus) in area of rich coral growth. Bali, Indonesia.

David Fleetham / Komodo dragon (Varanus komodoensis), the world's largest lizard. Rinca Island, Komodo National Park, Indonesia.

David Fleetham / Komodo dragon (Varanus komodoensis), with sailing-boat in background. Rinca Island, Komodo National Park, Indonesia.

David Fleetham / Florida Manatee (Trichechus manatus latirostris), Three Sisters Spring, Crystal River, Florida, USA. National Wildlife Federation Photo Contest Grand Prize WINNER 2010.

David Fleetham / Great white shark (Carcharodon carcharias) with mouth open, just below the surface off Guadalupe Island, Mexico.

David Fleetham / Galapagos shark (Carcharhinus galapagensis) group feeding at surface, Hawaii.

David Fleetham / Great white shark (Carcharodon carcharias) off Guadalupe Island, Mexico.

David Fleetham / Great white shark (Carcharodon carcharias), portrait. Guadalupe Island, Mexico.

David Fleetham / Guineafowl pufferfish (Arothron meleagris) puffed up in defence, Hawaii.

David Fleetham / Spinyhead blenny (Acanthemblemaria spinosa) in hard coral, Netherlands Antilles, Bonaire, Caribbean.

Alex Mustard / American crocodile (Crocodylus acutus) reflected in the surface as it floats, Jardines de la Reina, Gardens of the Queen National Park, Cuba. Caribbean Sea.

Ingo Arndt / Cape gannets (Morus capensis / Sula capensis) at nesting colony, zooming from tight to wide shot, Lamberts Bay, South Africa, December

Ingo Arndt / Cape fur seals (Arctocephalus pusillus) at colony, Cape Cross, Namibia, December

Ingo Arndt / Grizzly bear (Ursus arctos horribilis) mother with two cubs catching salmon, Lake Clark National Park, Alaska, USA, September

Ingo Arndt / Glaucous winged gull (Larus glaucescens) calling, Lake Clark National Park, Alaska, USA, August

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) waiting for salmon under moonlit sky, Lake Clark National Park, Alaska, USA, August

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) waiting for salmon at full moon, Lake Clark National Park, Alaska, USA, August

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) two cubs resting, Lake Clark National Park, Alaska, USA, August