Alex Mustard / Yellowtail tang (Zebrasoma xanthurum) male and female turn belly to belly during spawning to ensure fertilization. Temple, Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea. This action is very fast...

Martin Willis / Rainbow Lorikeet (Trichoglossus haematodus) pair preening during courtship, Magnetic Island, Queensland, Australia

Danny Green / Reindeer (Rangifer tarandus) hunkering down in snow during blizzard. Svalbard, Norway, April.

Theo Bosboom / Powerful waves rolling in at the Atlantic coast of Iceland near Dyrholey during a powerful winter storm. February 2016

Tony Wu / View down the throat of a male Zoarchias major eelpout (Zoarchias major) that has opened its mouth during a confrontation with another male. Yamaguchi Prefecture, Japan. Pacific Ocean.

Jack Dykinga / Saguaro cacti (Carnegia gigantea) at sunset, during a summer rain storm. Saguaro National Park, Sonoran Desert, Arizona, USA, August. Digital composite.

John Shaw / Black-browed albatross pair (Thalassarche melanophris) mutual grooming during copulation. New Island, Falkland Islands, November.

Shane Gross / Elkhorn corals (Acropora palmata) at night silhouetted by a scientist's light during the annual coral spawn. Abaco, Bahamas.

John Chan / Two male Southern Pacific rattlesnakes (Crotalus oreganus helleri) fighting during mating season. This behaviour is known as a "combat dance", and is used to determine dominance and the right to mate...

Sandesh Kadur / Slow motion clip of Amur falcons (Falco amurensis) congregating at roost site during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Sandesh Kadur / Amur falcons (Falco amurensis) congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Sandesh Kadur / Amur falcons (Falco amurensis) congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Neil Aldridge / Team of vets and conservation staff move a sedated White rhinoceros (Ceratotherium simum) into a comfortable resting position in a secure enclosure known as a boma during a translocation operation to...

Marie Read / Western Grebe (Aechmorphus occidentalis), pair during 'rushing' courtship display in which they run across water's surface in synchrony, near Escondido, California, USA, January.

Marie Read / Snow buntings (Plectrophenax nivalis) flock in flight during a snowstorm, New York, USA, January.

Marie Read / Canada geese (Branta canadensis) two during territorial fight in early spring, Ithaca. New York, USA

Marie Read / Common redpoll (Carduelis flammea), male perched in alder (Alnus rugosa) during a snowstorm in winter, New York, USA, January.

Marie Read / American avocets (Recurvirostra americana) two during aggressive (territorial) encounter, Bear River Migratory Bird Refuge, Utah, USA, May.

Ralph Pace / Olive Ridley Sea Turtle (Lepidochelys olivacea) females coming ashore to nest during arribada, Playa de Escobilla Sanctuary, Oaxaca, Mexico

Shane P. White / Tephra during volcanic eruption, Mount Yasur, Tanna Island, Vanuatu

Stefan Christmann / Adelie penguin (Pygoscelis adeliae) calling during courtship, Atka Bay, Queen Maud Land, Antarctica, December.

John Chan / Male California least tern (Sternula antillarum browni) presenting fish offering to female during mating, Huntington Beach, California, USA, May.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) breeding colony, males huddling on sea ice during polar night, incubating eggs, ice shelf in background. Atka Bay, Antarctica. July 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) colony huddled during polar night, males incubating eggs. Atka Bay, Antarctica. July 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) males in breeding colony huddling during winter storm. Atka Bay, Antarctica. July.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) males huddling whilst incubating eggs,under full moon during polar night, Atka Bay, Antarctica. July.

Stefan Christmann / Member of BBC Dynasties crew photographing on sea ice in light of full moon, during polar night. Atka Bay, Antarctica. July 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) males in breeding colony incubating eggs, huddling during winter storm. Penguins on outside repositioning themselves to gain protection from weather. Atka Bay, A...

Stefan Christmann / Sea ice, during polar night. Atka Bay, Antarctica. July 2017.

Stefan Christmann / Sea ice and iceberg during polar night. Atka Bay, Antarctica. July 2017.

Stefan Christmann / Moon bow, a halo around the moon during polar night. Sastrugi on sea ice in foreground. Atka Bay, Antarctica. June.

Stefan Christmann / Milky way and moonbow halo during polar night. Above Neumayer-Station III, Alfred-Wegener-Institut research station, Atka Bay, Antarctica. June 2017.

Stefan Christmann / Moon rising over sea ice during polar night. Atka Bay, Antarctica. June 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) walking across crack in sea ice during return to breeding colony. Atka Bay, Antarctica. April.

Stefan Christmann / Stars and milky way over Neumayer-Station III, Alfred-Wegener-Institut research station. During full moon. Atka Bay, Antarctica. April 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) group clambering up slope during journey to bring back food for young. Atka Bay, Antarctica. September.

Angelo Gandolfi / Forest fire in the Cerrado during dry season. Chapada dos Veadeiros National Park, Goias, Brazil. September 2010.

Paul Hobson / Red deer (Cervus elaphus) herd during rut in morning light. Derbyshire, England, UK. October.

Clay Bolt / Entomologist examining a large female Megachile bee during the hunt to rediscover Wallace's giant bee (Megachile pluto) on the island of Ternate, North Moluccas, Indonesia. January 2019

Glenn Bartley/ BIA / Black-mandibled Toucan (Ramphastos ambiguus) during rainfall, Costa Rica

David Allemand / Two Snow geese (Anser caerulescens) during migration, with dark clouds against the sun, Quebec, Canada, October.

Giri Cavale / Melanistic leopard / Black panther (Panthera pardus) on territorial patrol on track, Nagarahole National Park, Nilgiri Biosphere Reserve, Karnataka, India.

Remi Masson / Male Common toads (Bufo bufo) fighting underwater during mating season, with a pair mating Ain, Rhone-Alps, France, March.

Bernard Castelein / Klein Schietveld during drought, this land is normally flooded wetlandsland, Brasschaat, Belgium. August.

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

Eric Baccega / Giant panda (Ailuropoda melanoleuca) cub exploring during its outings in the enclosure. Yuan Meng, first giant panda ever born in France, age 10 months, Captive at Beauval Zoo, Saint Aignan sur Cher,...

Dave Bevan / Slow motion clip of a Jay (Garrulus glandarius) feeding from a peanut string during a snowstorm, Carmarthenshire, Wales, UK, November.

Espen Bergersen / Time lapse of people emptying plastic bags full of marine litter to show what has been collected during a beach clean, Tussoya, Troms, Norway, 2017.

Nick Upton / Pine marten (Martes martes) male standing on a feeding table in a soft release cage after arrival from Scotland, during a reintroduction project by the Vincent Wildlife Trust, Cambrian Mountains, Wale...

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chicks huddled together during a blizzard, Adelie Land, Antarctica, January.

Steven Kazlowski / Polar bear (Ursus maritimus) mother with two juveniles walking along ice edge during autumn freeze up, Beaufort Sea, off Arctic coast, Alaska

Denis-Huot / Cheetah (Acinonyx jubatus) female with cubs sitting in long grass during the dry season, Masai-Mara Game Reserve, Kenya. March.

David Pattyn / Great crested grebe (Podiceps cristatus) fluffing up its feathers, during courtship dance, whilst its mate dives underwater, The Netherlands. April.

David Pattyn / Black necked grebe (Podiceps nigricollis) pair chasing away another grebe during the courtship season. The Netherlands.April 2014

David Pattyn / Black necked grebe (Podiceps nigricollis) pair during courtship performing their courtship dance in the mating season. The Netherlands. April 2014

David Pattyn / Black necked grebe (Podiceps nigricollis) adult bird in breeding plumage approaching its partner in a vertical position during their courtship dance. The Netherlands.April 2014

David Pattyn / Black necked grebe (Podiceps nigricollis) pair swimming away during their courtship dance. The Netherlands.March 2014

David Pattyn / Black necked grebe (Podiceps nigricollis) pair chasing away another grebe during the mating season. The Netherlands.March 2014

Ingo Arndt / Villagers collecting eggs from Olive ridley sea turtles (Lepidochelys olivacea) during the first two days of the arribada (mass nesting event). This is the only place in the world where it is legal to...

Ingo Arndt / Olive ridley sea turtles (Lepidochelys olivacea) digging their nests by night with stars during an arribada (mass nesting event) to lay eggs, Pacific Coast, Ostional, Costa Rica.

Ingo Arndt / Olive ridley sea turtles (Lepidochelys olivacea) females coming ashore at twilight during an arribada (mass nesting event) to lay eggs, Pacific Coast, Ostional, Costa Rica.

Ingo Arndt / Olive ridley sea turtles (Lepidochelys olivacea) females coming ashore during an arribada (mass nesting event) to lay eggs, Pacific Coast, Ostional, Costa Rica.

Ingo Arndt / Christmas Island Red Crabs (Gecarcoidea natalis) crossing closed road, during annual migration, Christmas Island, Indian Ocean, Australian Territory, November 2009.

Ingo Arndt / Christmas Island Red Crabs (Gecarcoidea natalis) crossing road in huge numbers during annual migration, Christmas Island, Indian Ocean, Australian Territory

Ingo Arndt / Flock of Bramblings (Fringilla montifringilla) perched together in branches. It's estimated that four million individiuals return to roost during winter in Black Forest, Germany. February.

Ingo Arndt / Flock of Bramblings (Fringilla montifringilla) roosting together in branches. It's estimated that four million individiuals roost in the Black Forest, during winter months, Germany. February.

Ingo Arndt / Flock of Bramblings (Fringilla montifringilla) taking off / landing on branches. It's estimated that four million individiuals roost in the Black Forest, during winter months, Germany. February.

Ingo Arndt / Pea aphid (Acyrthosiphon pisum) giving birth (viviparous during the summer month), Germany. Winner of Fritz Polking portfolio prize, GDT 2012 competition.

Tony Wu / Humpback whales (Megaptera novaeangliae) male during a competetive heat run. Vava'u, Tonga, South Pacific.

Benjamin Olson / Cave at night during polar vortex, Lake Superior, Tettegouche State Park, Minnesota, multiple exposures

Glenn Bartley/ BIA / Collared Aracari (Pteroglossus torquatus) during rainfall, Costa Rica

Eric Sohn Joo Tan/ BIA / Black-winged Lapwing (Vanellus melanopterus) calling during defensive display, KwaZulu-Natal, South Africa

Thomas Hinsche/ BIA / Common Buzzard (Buteo buteo) during snowfall, Saxony-Anhalt, Germany

Jack Dykinga / Sand verbena (Abronia) flowering in a dried up bush, Anza-Borrego State Park, California, USA, March 2017. These plants are flowering during on largest 'super-bloom in years' caused by increased winte...

Jack Dykinga / Desert landscape with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. Anza-Borrego...

Jack Dykinga / Desert landscape at sunset, with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. An...

Jack Dykinga / Desert landscape with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. Anza-Borrego...

Jack Dykinga / Desert landscape with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. Anza-Borrego...

Jack Dykinga / Whipple Mountain foothills, with flowering Notch-leaf scorpion-weed (Phacelia crenulata) and Heartleaf evening primrose (Camissonia cardiophylla) with the Riverside and Big Maria Mountains in the back...

Jack Dykinga / Whipple Mountain foothills, with flowering Notch-leaf scorpion-weed (Phacelia crenulata) and Heartleaf evening primrose (Camissonia cardiophylla) with the Riverside and Big Maria Mountains in the back...

Jack Dykinga / Whipple Mountain foothills, with flowering Notch-leaf scorpion-weed (Phacelia crenulata) and Heartleaf evening primrose (Camissonia cardiophylla) with the Riverside and Big Maria Mountains in the back...

Jack Dykinga / 1563786 - - Desert landscape with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. An...

Jack Dykinga / Close up of flowering Sand verbena (Abronia) and Birdcage evening primrose (Oenothera deltoides) Anza-Borrego State Park, California, USA. March 2017. These plants are flowering during on largest 'su...

Jack Dykinga / Notch-leaf scorpion-weed (Phacelia crenulata) blooming around Desert agave (Agave desertii) in Glorieta Canyon, Anza-Borrego State Park, California, USA, March 2017. These plants are flowering during...

Jack Dykinga / Notch-leaf scorpion-weed (Phacelia crenulata) blooming around Desert agave (Agave desertii) in Glorieta Canyon, Anza-Borrego State Park, California, USA, March 2017. These plants are flowering during...

Jack Dykinga / Flowering Sand verbena (Abronia) and Birdcage evening primrose (Oenothera deltoides) close up, Anza-Borrego State Park, California, USA. March 2017. These plants are flowering during on largest 'supe...

Jack Dykinga / Whipple Mountain foothills, with flowering Notch-leaf scorpion-weed (Phacelia crenulata) and Heartleaf evening primrose (Camissonia cardiophylla) with the Riverside and Big Maria Mountains in the back...

Jack Dykinga / Desert landscape with flowering Sand verbena (Abronia), Desert gold (Geraea canescens), and Birdcage evening primrose (Oenothera deltoides), with the Santa Rosa Mountains in background. Anza-Borrego...

Alex Mustard / Yellow tube sponge (Aplysina fistularis) on a coral reef, with the camera rotated during the long exposure. East End, Grand Cayman, Cayman Islands. British West Indies. Caribbean Sea.

Yashpal Rathore / Demoiselle crane (Anthropoides virgo) resting on sand dunes during winter migration, Khichan, Western Rajasthan, India. March.

Yashpal Rathore / Demoiselle cranes (Anthropoides virgo) silhouetted at dusk on a wall during their winter migration.Khichan, Western Rajasthan, India. February.

Yashpal Rathore / Demoiselle cranes (Anthropoides virgo) flying at sunrise during migration. Khichan, Western Rajasthan, India. December.

Yashpal Rathore / Demoiselle crane (Anthropoides virgo) pair flying at sunrise during winter migration. Western Rajasthan, India. December.

Yashpal Rathore / Low angle view of Demoiselle crane (Anthropoides virgo) flying and feeding during winter migration. Khichan, Western Rajasthan, India. December.

Alan Murphy/ BIA / Boreal Chickadee (Poecile hudsonicus) during snowfall, Alaska

Jordi Chias / Two male Dusky groupers (Epinephelus marginatus) fighting for territory during mating season at 'baixa do meros', a small pinnacle at Formigas islets Protected area, near Santa Maria Island, Azores. F...