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

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

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.

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

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

Ross Hoddinott / Tank blocks from World War 2, along the shoreline on beach at sunset, Alnmouth beach, Northumberland, UK. October 2023.

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 / 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.

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.)

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

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 / 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 / Two Macqueen's bustard (Chlamydotis macqueenii) chicks, four days old. One chick pecks the other and then walks forward. National Avian Research Center, Abu Dhabi. Captive.

Paul Harcourt Davies / Common blue butterflies (Polyommatus icarus) pair mating on flower, male on the right, Umbria, Italy. May.

Staffan Widstrand / Two Ruff (Philomachus pugnax) males, fighting at lek site, Varanger Peninsula, Finnmark, Norway. June.

Staffan Widstrand / Three Ruff (Philomachus pugnax) males displaying on lek, with two females walking by, Varanger Peninsula, Finnmark, Norway. June.

Staffan Widstrand / Two Ruff (Philomachus pugnax) males, fighting at lek site with females in background, Varanger Peninsula, Finnmark, Norway. June.

Staffan Widstrand / Two Ruff (Philomachus pugnax) males, displaying at lek site, Varanger Peninsula, Finnmark, Norway. June.

Paul Harcourt Davies / Forester moths (Adscita statices) pair mating, Sibillini, Umbria, Italy. May.

Nigel Cattlin / Mummified Pea aphid (Acyrthosiphon pisum) parasitised by a Parasitoid wasp (Aphidius ervi) next to a healthy adult aphid on leaf, England, UK.

Nigel Cattlin / Two Parasitoid wasps (Diglyphus isaea) with a Leafminer larva in a leaf gallery, adult wasps used for biological pest control, England, UK.

Nigel Cattlin / Two Parasitoid wasps (Diglyphus isaea) with a Leafminer larva in a leaf gallery, adult wasps used for biological pest control, England, UK.

Nigel Cattlin / Potato aphids (Macrosiphum euphorbiae) one (black), parasitised by parasitoid wasp (Aphelinus abdominalis) alongside two healthy aphids, England, UK.

Nigel Cattlin / Two Parasitic wasps (Dacnusa sibirica) female, on a leaf, used for commercial pest control of Leafminers in protected crops, England, UK.

Jack Perks / Sea trout (Salmo trutta) pair courting, in preparation to spawning. The male quivers near the female and then she uses her tail fin to dig a shallow depression (a redd). Perthshire, UK, November.

Jack Perks / Mirror carp (Cyprinus carpio) swimming into frame and past the camera. The animal disappears into the murky water. Shropshire, UK.

Tim Laman / Two Gobies (Gobiidae) resting on a Sea fan (Gorgonia sp.), Raja Ampat Marine Park, Raja Ampat Islands, West Papua, Indonesia.

Sven Zacek / Two Red fox (Vulpes vulpes) juveniles, sitting in dewy meadow at sunrise, Valgamaa county, Southern Estonia.

Sven Zacek / Two Moose (Alces alces) juveniles, standing at edge of forest, looking back, Tartumaa county, Southern Estonia.

Henley Spiers / Green turtle (Chelonia mydas) juvenile, swimming in open ocean, with two Pilot fish (Naucrates ductor) and a Remora (Echeneidae) swimming alongside, Eastern Pacific Ocean. Endangered.

Emanuele Biggi / Kheper dung beetles (Kheper sp.) rolling a big ball of dung in search of a suitable place to bury it and lay eggs inside, South Africa.

Espen Bergersen / Two Orcas (Orcinus Orca) swimming at sea surface with mountains in background, Skjervoy, Troms, Norway, Norwegian Sea. October.

Espen Bergersen / Ruff (Philomachus pugnax) male, watching its Mosquito (Culicidae) prey, Troms, Norway. June. Cropped

Danny Green / European stonechat (Saxicola rubicola) male and juvenile perched on a tree stump, the juvenile begging for food, Dumfries and Galloway, Scotland, UK. May.

Danny Green / Northern gannets (Morus) pair, with nesting material in beak, head portrait, Great Saltee Island, Republic of Ireland. May.

Andrew Parkinson / Bengal tiger (Panthera tigris tigris) female juvenile, displaying aggressive behaviour towards its father, Bandhavgarh National Park, India. Endangered.

Graham Eaton / Bottlenose dolphins (Tursiops truncatus) surfacing, Abersoch, Gwynedd, Wales, UK, Cardigan Bay, May.

Andrew Parkinson / Two Rabbits (Oryctolagus cuniculus) juveniles, sitting in field close to the warren in evening light, Norfolk, UK. May.

Andrew Parkinson / Two Rabbits (Oryctolagus cuniculus) juveniles, sitting in field close to the warren in evening light, Isle of Lewis, Outer Hebrides, UK.July.

Andrew Parkinson / Two Rabbits (Oryctolagus cuniculus) sub-adults, sitting alert close to the warren, Norfolk, UK. May.

Andrew Parkinson / Rabbit (Oryctolagus cuniculus) juvenile, sitting upright in grassland with adult behind, Norfolk, UK. June.

Andrew Parkinson / Rabbit (Oryctolagus cuniculus) female, sitting upright, alert, with infant feeding on grass close by, Norfolk, UK. June.

Bret Charman / Two African bush elephants (Loxodonta africana) juvenile males, sparring, Mara Triangle Conservancy, Masai Mara, Kenya. Endangered.

Bret Charman / Two Red deer (Cervus elephus) stags rutting in thick morning mist on heathland, New Forest, Hampshire, UK. October.

Bret Charman / Two Arctic foxes (Vulpes lagopus) 'blue morph', in snow, female attacking male to defend her cubs, Hornstrandir Nature Reserve, Iceland. March.

Bret Charman / Crawshay's zebra (Equus quagga crawshayi) mare with foal, standing in area of open riverine forest, South Luangwa National Park, Zambia.

Bret Charman / Two Great grey owl (Strix nebulosa) chicks, perched in nest hole in dead tree, calling, Finland. July.

Bret Charman / Two Green-bearded helmetcrest (Oxypogon guerinii) fledglings perched on branch, sheltering from strong winds, Parque Nacional Natural Sumapaz, Colombia.

Bret Charman / Eastern grey kangaroo (Macropus giganteus) joey standing next to resting female in coastal grasslands, Narawntapu National Park, Tasmania, Australia.

Bret Charman / Roe deer (Capreolus capreolus) buck following a doe through long grass during the rut, South Downs National Park, Hampshire, UK. August.

Bret Charman / Two Platypus (Ornithorhynchus anatinus) fighting at surface of small lake, Tasmania, Australia.

Bret Charman / Bennett's wallaby (Notamacropus rufogriseus) female, suckling its joey in the rain on a high altitude meadow, Cradle Mountain National Park, Tasmania, Australia.

Bret Charman / Two White-tailed eagles (Haliaeetus albicilla) fighting over food mid-air, Lake Furen, Hokkaido, Japan.

Bret Charman / Sulphur-crested cockatoo (Cacatua galerita) pair, allopreening perched in Eucalyptus (Eucalyptus sp.) tree, Botanical Gardens, Sydney, New South Wales, Australia.

Joel Sartore / Photo Ark / Two MacQueen's bustard (Chlamydotis macqueenii) chicks, aged four days, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Two MacQueen's bustard (Chlamydotis macqueenii) chicks, aged four days, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Two MacQueen's bustard (Chlamydotis macqueenii) chicks, aged four days, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, head portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, portrait, National Avian Research Center, UAE. Captive.

Joel Sartore / Photo Ark / Arabian bustards (Ardeotis arabs) pair, male larger than the female, portrait, National Avian Research Center, UAE. Captive.

Alex Mustard / Yellow pygmy gobies (Lubricogobius exiguus) pair living inside a discarded toothpaste tube on the seabed, Bitung, North Sulawesi, Indonesia, Lembeh Strait, Molucca Sea.

Suzi Eszterhas / Meerkat (Suricata suricatta) female, suckling her pup, aged 3 weeks, Makgadikgadi Pans, Botswana.

Suzi Eszterhas / Meerkat (Suricata suricatta) female, suckling her pup, aged 3 weeks, Makgadikgadi Pans, Botswana.

Suzi Eszterhas / Two Meerkat (Suricata suricatta) pups, aged 2 weeks, at entrance to burrow, Makgadikgadi Pans, Botswana.

Suzi Eszterhas / Koala (Phascolarctos cinereus) female carrying joey, aged 7 months, on her back, being held by veterinary nurse, Currumbin Wildlife Hospital, Queensland, Australia. October, 2015.

Suzi Eszterhas / Two Tawny frogmouths (Podargus strigoides) rescued after being hit by a car, being hand fed by wildlife sanctuary director, Bonorong Wildlife Sanctuary, Tasmania, Australia. October, 2015.

Suzi Eszterhas / Two Tawny frogmouths (Podargus strigoides) rescued after being hit by a car, being hand fed by wildlife sanctuary director, Bonorong Wildlife Sanctuary, Tasmania, Australia. October, 2015.

Joel Sartore / Photo Ark / Ferruginous ducks (Aythya nyroca) pair, portrait, Sylvan Heights Bird Park. Captive.

Joel Sartore / Photo Ark / White-breasted cormorant (Phalacrocorax lucidus) pair, head portrait, Audubon Zoo. Captive, occurs in Africa.

Joel Sartore / Photo Ark / Sumatran orangutan (Pongo abelii) infant aged 11 months, and Bornean orangutan (Pongo pygmaeus) infant aged 11 months, hugging, Taman Safari, West Java, Indonesia. Captive. Critically endangered.

Joel Sartore / Photo Ark / Sumatran orangutan (Pongo abelii) infant aged 11 months, and Bornean orangutan (Pongo pygmaeus) infant aged 11 months, hugging, Taman Safari, West Java, Indonesia. Captive. Critically endangered.

Joel Sartore / Photo Ark / Sumatran orangutan (Pongo abelii) infant aged 11 months, and Bornean orangutan (Pongo pygmaeus) infant aged 11 months, hugging, Taman Safari, West Java, Indonesia. Captive. Critically endangered.

Joel Sartore / Photo Ark / Two White-headed brown lemurs (Eulemur albifrons) male and female siblings, female on right, portrait, Naples Zoo. Captive, occurs in Madagascar.

David Fleetham / Gorgonian gobies (Bryaninops amplus) pair, resting next to their eggs on Wire coral (Cirrhipathes sp.), Hawaii, Pacific Ocean.

Will Watson / Arch over main doorway at St Mary & St David Church, with Romanesque carvings featuring a dragon eating its own tail, two fishes and and beaked head, Kilpeck, Herefordshire, England, UK, 2015. Carved...

Colin Varndell / Beech trees (Fagus sylvatica) in woodland, Bolderwood Ornamental Drive, New Forest National Park, Hampshire, November.

Neil Aldridge / Spotted hyena (Crocuta crocuta) young adult standing and looking around, in early morning light. Another Spotted hyena runs in and through the frame. Okavango Delta, Botswana.

Neil Aldridge / Two Red lechwe (Kobus leche) females jumping over a small channel in a swamp, before leaving frame. Another Red lechwe is grazing alongside an African sacred ibis (Threskiornis aethiopicus) which is f...

Neil Aldridge / Spotted hyenas (Crocuta crocuta) standing near a kill with their tails raised, showing excitement. One animal yawns and then both walk off and out of the frame. Okavango Delta, Botswana. Sequence 3/3...

Neil Aldridge / Spotted hyenas (Crocuta crocuta) near a kill with their tails raised, showing excitement. Both animals are investigating, sniffing the kill. One animal stops, looks up and then walks away. Okavango D...

Neil Aldridge / Spotted hyenas (Crocuta crocuta) near a kill with their tails raised, showing excitement. One animal is sniffing the kill and then the other also investigates it. Okavango Delta, Botswana. Sequence 1...

David Tipling / Black guillemots (Cepphus grylle) swimming in sea, showing winter plumage, Lerwick Harbour, Shetland, Scotland, UK, November. Red reflection on water from boat.

David Tipling / Black guillemots (Cepphus grylle) swimming in sea, showing winter plumage, Lerwick Harbour, Shetland, Scotland, UK, November. Red reflection on water from boat.

David Tipling / Hedgehogs (Erinaceus europaeus) feeding from food bowl on garden patio, Holt, Norfolk, England, UK, July.

Nick Upton / Red-billed chough (Pyrrhocorax pyrrhocorax) pair collecting nesting material beside eroded sandy cliff, Cornwall, UK, April.

Nick Upton / Red-billed chough (Pyrrhocorax pyrrhocorax) pair perching on coastal cliff as one bird calls, Cornwall, UK, April.