Andres M. Dominguez / Eurasian kingfisher (Alcedo atthis) male, perched on branch over pond with tadpole prey in beak, backlit at dawn, Sierra de Grazalema Natural Park, Cadiz, Spain. October.

Andres M. Dominguez / Eurasian kingfisher (Alcedo atthis) male, perched on a rock in pool, backlit at dawn, Sierra de Grazalema Natural Park, Cadiz, Spain. October.

Dr. Axel Gebauer / Aerial view of Red deer (Cervus elaphus) walking through pond with Water caltrop (Trapa natans) and blue bacteria, surrounded by Reedbeds (Phragmites australis), Biosphere Reserve, Upper Lusatia, Pola...

Ann & Steve Toon / Three Giraffes (Giraffa camelopardalis) silhouetted at sunset, Chobe National Park, Botswana.

Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) in flight after dipping into water to cool down and drink, Myuna Wetlands, Doveton, Victoria, Australia.

Doug Gimesy / Little pied cormorant (Microcarbo melanoleucos) standing on intertidal rocks, feeding on fish prey, Port Philip Bay, Victoria, Australia.

Gabriel Rojo / Geoffroy's cat (Leopardus geoffroyi) walking past seaweed covered rocks on beach, Punta Norte Nature Reserve, Peninsula Valdes, Chubut Province, Patagonia, Argentina.

Gabriel Rojo / Geoffroy's cat (Leopardus geoffroyi) walking along beach with Gulls (Larus sp.) in background, Punta Norte Nature Reserve, Peninsula Valdes, Chubut Province, Patagonia, Argentina.

George Sanker / Coyote (Canis latrans) hunting in a wetland meadow in summer, Yellowstone National Park, Wyoming, USA. June.

Jussi Murtosaari / Two Brown bear (Ursus arctos) males, fighting, Finland. August.

Jussi Murtosaari / Fieldfare (Turdus pilaris) perched in Rowan (Sorbus sp.) tree, feeding on berries, Finland. October.

Jussi Murtosaari / Blue-cheeked bee-eater (Merops persicus) perched on branch, Finland. June.

Jussi Murtosaari / Two Broad-bordered bee hawkmoths (Hemaris fuciformis) nectaring on wildflower, Finland. July.

Jussi Murtosaari / Grey wolf (Canis lupus) shaking fur dry after swimming, Finland. August.

Jussi Murtosaari / Common glow-worm (Lampyris noctiluca) female, resting on leaf, glowing, Finland. July.

Jussi Murtosaari / Bank vole (Clethrionomys glareolus) standing on hind legs, feeding on Strawberry (Fragaria sp.) leaves, Finland. July.

Jussi Murtosaari / Lesser purple emperor butterfly (Apatura ilia) male, in flight, Finland. July.

Jussi Murtosaari / Peacock butterfly (Aglais io) in flight over wildflowers, Finland. May.

Linda Pitkin / Green turtle (Chelonia mydas) resting on seabed feeding on Seagrass (Halophila stipulacea) with a Remora (Echeneis naucrates) on its back and shoals of small fish swimming around, Marsa Alam, Egypt, R...

Linda Pitkin / Barrel sponge (Xestospongia testudinaria) on reef with shoal of Barracuda (Sphyraena sp.) in background, Tubbataha Reefs Natural Park, Palawan, Philippines, Sulu Sea.

Linda Pitkin / Anthias (Pseudanthias sp.) and Damselfish (Chromis sp.) swimming over coral reef with Acropora (Acropora sp.) corals and Fire coral (Millepora sp.), Tubbataha Reefs Natural Park, Palawan, Philippines,...

Mark Carwardine / European hare (Lepus europaeus) sitting alert at edge of woodland, Hungary. June.

Mark Carwardine / European swallow (Hirundo rustica) flying low over water to drink, Hungary. June.

Mark Carwardine / Humpback whale (Megaptera novaeangliae) surfacing, Antarctic Peninsula, Southern Ocean.

Mark Carwardine / Brown bear (Ursus arctos) female, standing at edge of river, Great Bear Rainforest, British Columbia, Canada. October.

Marie Read / Varied thrush (Ixoreus naevius) male, perched on branch, singing in spring, Eagle River, Alaska, USA. May.

Marie Read / Snow buntings (Plectrophenax nivalis) large flock taking flight in winter, Vermont, USA. January.

Marie Read / Two Pigeon guillemots (Cepphus columba) in flight over rippling water, Haida Gwaii, British Columbia, Canada. May.

Marie Read / Pacific loons (Gavia pacifica) pair in breeding plumage, on water, Anchorage, Alaska, USA. May.

Marie Read / Northern parula (Parula americana) male in breeding plumage, perched in flowering Eastern redbud (Cercis canadensis) in spring, Ohio, USA. April.

Oliver Hellowell / Red squirrel (Sciurus vulgaris) standing on mossy rock in woodland garden, Perthshire, Scotland, UK. September. Cropped.

Oliver Hellowell / Red squirrel (Sciurus vulgaris) sitting upright among heather, in woodland garden, Perthshire, Scotland, UK. September. Cropped.

Oliver Hellowell / Red squirrel (Sciurus vulgaris) sitting on mossy rock in woodland garden, Perthshire, Scotland, UK. September. Cropped.

Oliver Hellowell / Red squirrel (Sciurus vulgaris) standing at base of Pine tree in woodland garden, Perthshire, Scotland, UK. September. Cropped.

Pal Hermansen / Melodius blackbird (Dives dives) attempting to catch a butterfly which is flying behind a plexiglass window, Costa Rica.

Pal Hermansen / Musk ox (Ovibos moschatus) pair mating, Dovrefjell-Sunndalsfjella National Park, Norway. September.

Pal Hermansen / Brimstone butterfly (Gonepteryx rhamni) in flight in bright sunshine, Follo, Akershus, Norway. July.

Pal Hermansen / Satyr pug moth (Eupithecia satyrata) flying off from flowerhead in meadow, Lofoten, Norway. June. Multiple-exposure.

Pal Hermansen / Yelllow dung fly (Scathophaga stercoraria) pair, mating on sheep dung, Lofoten, Norway. June.

Pal Hermansen / Group of male Toads (Bufo bufo) trying to mate with female, underwater in small lake, Akershus, Norway. May.

Ripan Biswas / Bombay night frog (Nyctibatrachus humayuni) egg cluster, with tadpoles visible inside translucent eggs, on leaf, Amboli, Maharastra, India.

Richard Flack / Böhm's bee-eater (Merops boehmi) perched on thin branch of wild Mango (Mangifera sp.) tree in riparian woodland, Thangadzi River Conservancy, Southern Malawi.

Ross Hoddinott / Group of Four-spotted chaser dragonflies (Libellula quadrimaculata) roosting on plant stem, backlit in the early morning light, Ham Wall RSPB Nature Reserve, Somerset Levels, UK. June.

Roger Powell / Red-throated diver (Gavia stellata) male, running over the water at speed and taking flight, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Two Ruffs (Calidris pugnax) male, fighting at the lek, Pokka, Finland, Lapland. May.

Roger Powell / Two Ruffs (Calidris pugnax) male, fighting at the lek, Pokka, Finland, Lapland. May.

Roger Powell / Four Greylag geese (Anser anser) flying low over lake, East Chevington Reserve, Druridge Bay, Northumberland, UK. November.

Roger Powell / Bearded vulture (Gypaetus barbatus) juvenile, landing among a group of Griffon vultures (Gyps fulvus) at feeding site with a wooded hillside behind, Lamiana, Aragon, Spanish Pyrenees, Spain. April.

Roger Powell / Two Bearded vultures (Gypaetus barbatus) in courtship display over a hillside, immature male trying to talon grapple with a mature female, Lamiana, Aragon, Spanish Pyrenees, Spain. April.

Roger Powell / Two Bearded vultures (Gypaetus barbatus) fighting over food, one with wings spread in threatening posture, Lamiana, Aragon, Spanish Pyrenees, Spain. April.

Sven Zacek / Common blue damselflies (Enallagma cyathigerum) pair, in flight over bog pool, Nigula Nature Protection Area, Parnumaa county, Estonia.

Sven Zacek / Capercaillie (Tetrao urogallus) male, with some tail feathers missing, lekking at sunset, Tartumaa county, Estonia.

Sven Zacek / Capercaillie (tetrao urogallus) male, lekking perched on top of a Pine tree at dusk, Tartumaa county, Estonia.

Tui De Roy / Monarch butterflies (Danaus plexippus) resting on trees in wintering grounds in the mountains of central Mexico, El Rosario Butterfly Sanctuary, Michoacan, Mexico.

Tui De Roy / Green turtles (Chelonia mydas) basking at dusk on beach, probably to kill ectoparasites and seaweed growth on their shells, Maui Island, Hawaii. Endangered.

Tui De Roy / Panamic horse conch (Triplofusus giganteus) in tidepool, Santiago Island, Galapagos Islands.

Tui De Roy / Green turtle (Chelonia mydas) swimming with school of Barracuda (Sphyraena sp.) behind, Cousins Rock, near Santiago Island, Galapagos Islands. Endangered.

Tui De Roy / Group of Green turtles (Chelonia mydas) basking at sunset, probably to kill ectoparasites and seaweed growth on their shells, Maui Island, Hawaii. Endangered.

Tui De Roy / Monarch butterflies (Danaus plexippus) covering Fir trees on wintering grounds in the mountains of central Mexico, El Rosario Butterfly Sanctuary, Michoacan, Mexico.

Tui De Roy / Kemp's ridley turtle (Lepidochelys kempii) female, coming ashore to nest in daylight, Rancho Nuevo Beach, Tamaulipas, Mexico. Critically endangered.

Tui De Roy / Kemp's ridley turtle (Lepidochelys kempii) female, coming ashore to nest in daylight, Rancho Nuevo Beach, Tamaulipas, Mexico. Critically endangered.

Staffan Widstrand / RF - Two Ruffs (Philomachus pugnax) male, fighting at lek site, Varanger Peninsula, Finnmark, Norway. June. (This image may be licensed either as rights managed or royalty free.)

Staffan Widstrand / RF - Atlantic guillemot (Uria aalge) standing on rock spreading its wings at sunset, with colony behind, Hornoya bird cliff Island, Vardoe, Varanger Peninsula, Finnmark, Norway. June. (This image may...

Staffan Widstrand / RF - Atlantic puffin (Fratercula arctica) portrait, Hornoya bird cliff Island, Vardoe, Varanger Peninsula, Finnmark, Norway. June. (This image may be licensed either as rights managed or royalty free....

Terry Whittaker / Atlantic puffin (Fratercula arctica), Grimsey Island, Iceland, June.

Guy Edwardes / Southern festoon butterflies (Zerynthia polyxena), newly emerged adults resting on their foodplant, Birthwort (Aristolochia clematitis), near Bratsigovo, Bulgaria, May.

Guy Edwardes / European pond turtle/terrapin (Emys orbicularis) swimming in pond with head above water and a fly resting on its snout, near Bratsigovo, Bulgaria, May

Guy Edwardes / Apollo butterflies (Parnassius apollo) roosting, Rhodope Mountains, Bulgaria, June.

Guy Edwardes / Black-veined white butterflies (Aporia crataegi) roosting on Burnt orchid (Orchis ustulata), Rhodope Mountains, Bulgaria, June.

Guy Edwardes / Silver-studded blue (Plebejus argus), backlit at sunset, Rhodope Mountains, Bulgaria, June

Guy Edwardes / Spoonwing lacewing (Nemoptera sinuata), warming itself at sunrise, Rhodope Mountains, Bulgaria, June

Guy Edwardes / Spotted fritillary (Melitaea didyma) larva/caterpillar, near Bratsigovo, Bulgaria June

Joel Sartore / Photo Ark / Blunt-nosed leopard lizard (Gambelia sila) looking around. The animal leaves the frame. Fresno Chaffee Zoo, California. Captive.

Joel Sartore / Photo Ark / Close up of a Timber rattlesnake's (Crotalus horridus) tail. It is vibrating its tail as a threat display. Verve Biotech, Waverly, Nebraska. Captive.

Joel Sartore / Photo Ark / Timber rattlesnake (Crotalus horridus) performing threat display by vibrating tail, Verve Biotech, Waverly, Nebraska. Captive.

Joel Sartore / Photo Ark / Timber rattlesnake (Crotalus horridus) performing threat display by vibrating tail, Verve Biotech, Waverly, Nebraska. Captive.

Joel Sartore / Photo Ark / Grandidier's mongoose / Grandidier's vontsira (Galidictis grandidieri) looking around, Al Bustan Zoological Centre. Captive. Endangered.

Joel Sartore / Photo Ark / Eastern quoll (Dasyurus viverrinus) lying down and looking at the camera, Zoo Leipzig. Captive. Endangered.

Joel Sartore / Photo Ark / Proboscis monkey (Nasalis larvatus) male using its hands to pick food up and eat. The animal leaves the frame. Taman Safari Prigen. Captive. Endangered.

Joel Sartore / Photo Ark / Hawaiian monk seal (Neomonachus schauinslandi) vocalising. The animal's head appears from bottom of the frame. Minnesota Zoo. Captive. Endangered.

Joel Sartore / Photo Ark / Marbled cat (Pardofelis marmorata longicaudata) looking towards the camera and lying down. The animal hisses and bares its teeth. Al Bustan Zoological Centre, Sharjah. Captive.

Joel Sartore / Photo Ark / San Bernardino kangaroo rat (Dipodymys merriami parvus) looking at the camera, then the animal partially leaves frame, San Diego Zoo Safari Park, Escondido, California. Captive. Federally endangered.

Joel Sartore / Photo Ark / Slender-horned gazelle (Gazella leptoceros) appearing from bottom of frame and looking around, San Diego Zoo Safari Park. Captive. Endangered.

Joel Sartore / Photo Ark / Okapi (Okapia johnstoni) juvenile male, two months old, flicking a fly off its face with its tongue. Leucistic individual, named 'Mzimu' (meaning ghost in Swahili), Al Bustan Zoological Centre, Sharja...

Joel Sartore / Photo Ark / Okapi (Okapia johnstoni) juvenile male, two months old, standing and looking around. Leucistic individual, named 'Mzimu' (meaning ghost in Swahili), Al Bustan Zoological Centre, Sharjah. Captive. Enda...

Joel Sartore / Photo Ark / Eastern black bear (Ursus americanus americanus) juvenile, four months old, looking at the camera and moving curiously towards the camera, North Carolina Zoo Wildlife Rehabilitation Center, USA. Contr...

Joel Sartore / Photo Ark / African upside-down jellyfish (Cassiopea depressa) moving 'bell', Oklahoma Aquarium. Captive.

Joel Sartore / Photo Ark / Giant vietnamese centipede (Scolopendra dehaani) cleaning antennae with mandibles, Verve Biotech, Waverly, Nebraska. Captive.

Joel Sartore / Photo Ark / Bigclaw crayfish (Faxonius placidus) female oxygenating eggs by fanning them, upper Duck River, Coffee County, Tennessee, USA. Controlled conditions.

Joel Sartore / Photo Ark / Spanish dancer nudibranch (Hexabranchus sanguineus) with an Emperor shrimp (Zenopontonia rex) moving on top of it, Farglory Ocean Park, Hualien. Captive.

Joel Sartore / Photo Ark / Common topknot (Zeugopterus punctatus) moving its fins, Aquazoo Loebbecke Museum, Dusseldorf. Captive.

Joel Sartore / Photo Ark / Close up of a Common topknot (Zeugopterus punctatus) head. The animal is looking at the camera. Aquazoo Loebbecke Museum, Dusseldorf. Captive.

Joel Sartore / Photo Ark / Close up of a Coral grouper (Cephalopholis miniata) head. The animal looks around. Oklahoma Aquarium. Captive.

Joel Sartore / Photo Ark / Bigmouth chub (Nocomis platyrhynchus) looking around, Aquatic Wildlife Conservation Center, Marion, Virginia. Captive.

Joel Sartore / Photo Ark / Buffalo darter (Ehtheostoma bison), Brush Creek, Lewis County, Tennessee, USA. Controlled conditions.

Joel Sartore / Photo Ark / Sulawesi white-collared kingfisher (Todiramphus chloris) defecating, San Diego Zoo. Captive.