Morley Read / Slow motion clip of a group of male Mallards (Anas platyrhynchos) competing violently to mate with a single female, Cornwall, England, UK, May 2018.

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

Jami Tarris / Polar Bear (Ursus maritimus) hunting Bearded Seal (Erignathus barbatus) pup, Spitsbergen, Svalbard, Norway

Juergen & Christine Sohns / African Lion (Panthera leo) six week old cubs, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Juergen & Christine Sohns / Meerkat (Suricata suricatta) pair on alert, Tswalu Game Reserve, South Africa

Anup Shah / Olive Baboon (Papio anubis) male with three month old young, Gombe National Park, Tanzania

Martin Willis / Splendid Fairywren (Malurus splendens) female and male, Queensland, Australia

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

Martin Willis / Budgerigar (Melopsittacus undulatus) father with begging chick at nest cavity, Queensland, Australia

Danny Green / Polar bear (Ursus maritimus) and two cubs feeding on Whale carcass. Svalbard, Norway, July.

Danny Green / Arctic fox (Vulpes lagopus), two in snow covered landscape. Svalbard, Norway, April 2019.

Danny Green / Ringed seal (Pusa hispida) and pup resting on ice. Svalbard, Norway. April.

Danny Green / Reindeer (Rangifer tarandus), two standing on ridge in blizzard. Svalbard, Norway. April.

Danny Green / Reindeer (Rangifer tarandus), two play fighting in snow. Svalbard, Norway, April.

Danny Green / Reindeer (Rangifer tarandus), two standing on ridge in snow. Svalbard, Norway, April.

Danny Green / Polar bear (Ursus maritimus) two walking in snowy landscape. Svalbard, Norway, April 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.

Nick Garbutt / King penguin (Aptenodytes patagonicus), two sleeping on snow. Grytviken, South Georgia. March.

Alex Mustard / Southern stingray (Dasyatis americana) two swimming over sand bar, under stormy sky. Grand Cayman, Cayman Islands. British West Indies.

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) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Oscar Dewhurst / Mute swan (Cygnus olor), two cygnets sheltering under parent's wing. Richmond Park, London, England, UK. April.

Guy Edwardes / Marbled white (Melanagria galathea), two butterflies on Pyramidal orchid (Anacamptis pyramidalis). Badbury Rings, Wimborne Minster, Dorset, England, UK. June.

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.

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

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) predating urchin, Anilao, Philippines

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) male and female, Whyalla, South Australia, Australia

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) males fighting over female, Whyalla, South Australia, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning female Stocky Anthias (Pseudanthias hypselosoma), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Whitemouth Moray (Gymnothorax meleagris) being cleaned by Cleaner Wrasse (Labroides sp) juvenile, Christmas Island, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Yellow-edged Moray (Gymnothorax flavimarginatus), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Honeycomb Moray Eel (Gymnothorax favagineus), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Goldbelly Cardinalfish (Apogon apogonides), Tulamben, Bali, Indonesia

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.

Ingo Arndt / Mountain Lion (Puma concolor) hunting Guanaco (Lama guanicoe) male, Torres del Paine National Park, Patagonia, Chile, sequence 3 of 12. Joint winner of the Mammal Behaviour Category of the Wildlife Ph...

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

Mark Raycroft / Woodland Caribou (Rangifer tarandus caribou) mother nursing calf, Newfoundland, Canada

Suzi Eszterhas / Leopard (Panthera pardus) mother and eight-month-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) six-week-old cub nursing, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) six-week-old cubs playing, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) six-week-old cub nuzzling mother, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother playing with her six-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub playing with mother's tail, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub playing with mother's tail, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother and five-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother grooming five-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub playing with mother, Jao Reserve, Botswana

Winfried Wisniewski / African Lion (Panthera leo) males nuzzling, Masai Mara, Kenya

SCOTLAND: The Big Picture / Cuckoo wrasse (Labrus bergylta) and Ballan wrasse (Labrus bergylta) on the wreck of Jayne, Shetland

Espen Bergersen / Aerial shot of two Killer whales (Orcinus orca) swimming inside a shoal of Atlantic herring (Clupea harenguis), hunting, with one Killer whale tail slapping to stun the Herring, Sommaroy, Troms, Norwa...

Espen Bergersen / Aerial shot of two Killer whales (Orcinus orca) swimming into a huge shoal of Atlantic herring (Clupea harenguis), hunting, Sommaroy, Troms, Norway, January.

Espen Bergersen / Aerial shot of two Killer whales (Orcinus orca) swimming near to a huge shoal of Atlantic herring (Clupea harenguis), hunting, Sommaroy, Troms, Norway, January.

Espen Bergersen / Aerial shot of two Killer whales (Orcinus orca) swimming inside a shoal of Atlantic herring (Clupea harenguis), hunting, Sommaroy, Troms, Norway, January.

Espen Bergersen / Aerial shot of two Killer whales (Orcinus orca) swimming inside a large shoal of Atlantic herring (Clupea harenguis), hunting, Sommaroy, Troms, Norway, January.

Wim van den Heever / King penguins (Aptenodytes patagonicus) at sunrise. Two males and a female, with the males fighting for the attention of the female. Falklands Islands. 2018 Wildlife Photographer of the Year LUMIX Peo...

Alan Murphy/ BIA / Northern Caracara (Caracara cheriway) pair fighting, Texas

Alan Murphy/ BIA / Belted Kingfisher (Megaceryle alcyon) fishing, Texas

Alan Murphy/ BIA / Baltimore Oriole (Icterus galbula) males fighting, Texas

Alan Murphy/ BIA / Baltimore Oriole (Icterus galbula) males fighting, Texas

Willi Rolfes/ BIA / Alpine Marmot (Marmota marmota) parent with young feeding, Hohe Tauern National Park, Austria

Willi Rolfes/ BIA / Alpine Marmot (Marmota marmota) parent feeding with begging young, Hohe Tauern National Park, Austria

Willi Rolfes/ BIA / Alpine Marmot (Marmota marmota) parent with young feeding, Hohe Tauern National Park, Austria

Cyril Ruoso / Ring-tailed Lemur (Lemur catta) mother with young drinking, Anja Park, Madagascar

Richard Du Toit / Northern Giraffe (Giraffa camelopardalis) calves, iSimangaliso Wetland Park, KwaZulu-Natal, South Africa

Gary Bell/ Oceanwide / Clown Anemonefish (Amphiprion ocellaris) in sea anemone, Australia

Gary Bell/ Oceanwide / Pink Anemonefish (Amphiprion perideraion) in sea anemone, Great Barrier Reef, Australia

Markus Varesvuo / Jay (Garrulus glandarius), two fighting in mid-air with another observing. Norway. October.

Markus Varesvuo / Jay (Garrulus glandarius), two fighting in mid-air with another observing. Norway. October.

George Sanker / Arctic tern (Sterna paradisaea), two fighting in mid-air. Machias Seal Island, New Brunswick / Maine, Canada / USA. July.

Flip Nicklin / Humpback Whale (Megaptera novaeangliae) mother and calf, Maui, Hawaii

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two males, one brooding young chick, the other incubating hatching egg. Atka Bay, Antarctica. August. Series 4/4.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two males, one brooding young chick, the other incubating hatching egg. Atka Bay, Antarctica. August. Series 3/4.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two males, one brooding young chick, the other incubating hatching egg. Atka Bay, Antarctica. August. Series 2/4.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two males, one brooding young chick, the other incubating hatching egg. Atka Bay, Antarctica. August. Series 1/4.

Stefan Christmann / Orca (Orcinus orca), two spyhopping in gap in sea ice. Atka Bay, Antarctica. January.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) chicks aged 20-24 weeks stretching wings, in moult whilst parents fish at sea. Atka Bay, Antarctica. January.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two adults brooding chicks. Atka Bay, Antarctica. September.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two adults brooding chicks. One chick exhibiting aggression towards other. Atka Bay, Antarctica. September.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two adults with chicks aged six to eight weeks. Atka Bay, Antarctica. September.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two chicks aged six to eight weeks brooding on parents' feet. Atka Bay, Antarctica. September.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two chicks aged six to eight weeks brooding on parents' feet, one vocalising. Atka Bay, Antarctica. September.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two chicks aged six to eight weeks huddling together. Atka Bay, Antarctica. September.

Sven Zacek / Honey bee (Apis mellifera), two frozen on pond ice after flying out too early. Valgamaa, Southern Estonia. March.

John Cancalosi / American toads (Anaxyrus americanus), several males competing to mate with female, Maryland, USA, April.

Paul Hobson / Red fox (Vulpes vulpes), two cubs play fighting. Sheffield, England, UK. May.

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) mother cleaning fawn, Montana

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) doe cleaning newborn fawn, Montana