Owen Newman / Male Red kangaroos fighting {Macropus rufus} Sturt NP, New South Wales Australia

Sylvain Cordier / RF-Gelada baboon (Theropithecus gelada) dominant male running. Debre Libanos, Rift Valley, Ethiopia. 2017. (This image may be licensed either as rights managed or royalty free)

Klein & Hubert / Meerkat (Suricata suricatta) alpha female nursing her one month old pups on the den, Kalahari Desert, Botswana.

Carol Walker / Two wild pinto Mustang stallions battle for dominance in Sand Wash Basin, Colorado, USA.

Andy Rouse / Great crested grebe (Podiceps cristatus cristatus) courtship dance, Cardiff, UK, March.

Krijn Trimbos / Great crested grebe (Podiceps cristatus) two in territorial fight, The Netherlands, March.

Cyril Ruoso / Bonobo (Pan paniscus) male and female copulating, Lola ya Bonobo Sanctuary, Democratic Republic of Congo

Ole Jorgen Liodden / Waved albatross (Phoebastria irrorata) pair in courtship display, Espanola, Galapagos Islands. Critically endangered species.

Andy Rouse / Bengal tiger (Panthera tigris tigris) 11 month cubs with mother 'T19 Krishna' in background, Ranthambhore National Park, India.

Markus Varesvuo / Black grouse (Lyrurus tetrix) mating in snow, Utajarvi, Finland, May.

David Pattyn / Great crested grebe (Podiceps cristatus) pair performing their 'weed dance' in which they take a vertical position in front of each other and offer plant material to each other. The Netherlands. March...

Denis-Huot / Lion (Panthera leo) mating, Masai-Mara Game Reserve, Kenya. Vulnerable species.

Denis-Huot,Denis-Huot / Lion (Panthera leo) mating, Masai-Mara Game Reserve, Kenya. Vulnerable species.

Anup Shah / Topi (Damaliscus lunatus jimela) two males sparring, with another approaching, Masai Mara National Reserve, Kenya. March

Anup Shah / Western lowland gorilla (Gorilla gorilla gorilla) dominant male silverback 'Makumba' aged 32 years feeding on rotten wood from a tree while his juvenile son 'Tembo' aged 4 years waits his turn, Bai Ho...

Anup Shah / Western lowland gorilla (Gorilla gorilla gorilla) dominant male silverback 'Makumba' aged 32 years feeding on rotten wood from a tree while female 'Malui' and their juvenile son 'Tembo' aged 4 years s...

Anup Shah / Western lowland gorilla (Gorilla gorilla gorilla) dominant male silverback 'Makumba' aged 32 years feeding on rotten wood from a tree while female 'Malui' and their juvenile son 'Tembo' aged 4 years s...

David Pattyn / Alpine ibex (Capra ibex) adult male chasing two young males away, Gran Paradiso National Park, Italy, July

David Pattyn / Red necked grebe (Podiceps grisegena) approaching a competitor in an attempt to drive him away during the courting season, Danube area, Bulgaria, April

Anup Shah / African elephants (Loxodonta africana) sparring, Masai Mara National Reserve, Kenya, August

Charlie Summers / Plains Zebra (Equus quagga) in a dominance fight with dust flying, Lake Magadi, Serengeti, Tanzania.

Andy Rouse / Agile wallabies (Macropus agilis) sparring and fighting, Bamarru Plains, Northern Territories, Australia

Andy Rouse / Agile wallabies (Macropus agilis) sparring and fighting, Bamarru Plains, Northern Territories, Australia

Carol Walker / Wild horses / Mustangs, two stallions play fighting, Pryor Mountains, Montana, USA, July 2010

George Sanker / Bison (Bison bison) two males head to head, Yellowstone NP, Wyoming, USA

Rolf Nussbaumer / Northern mockingbird (Mimus polyglottos) adult fighting with Golden-fronted Woodpecker (Melanerpes aurifrons) female over Texas Prickly Pear Cactus (Opuntia lindheimeri) Dinero, Lake Corpus Christi, S...

Bertie Gregory / 2020VISION / Red deer (Cervus elaphus) stags fighting during rut, Richmond Park, London, England, UK, October. Did you know? Richmond Park deer herds are descended from historic medieval royal hunting stock.

Bertie Gregory / 2020VISION / Red deer (Cervus elaphus) stags fighting during rut, Richmond Park, London, England, UK, October

Bertie Gregory / 2020VISION / Red deer (Cervus elaphus) stags fighting during rut, with blocks of flats in the background, Richmond Park, London, England, UK, October

Marie Read / Two Black-capped chickadees (Poecile atricapillus) in mid-air fight by a sunflower, New York, USA, February

Juan Carlos Munoz / Two White Tailed Sea Eagle (Haliaeetus albicilla) fighting in acrobatic flight as Raven (Corvus corax) looks on and a Herring Gull (Larus argentus) flies past. Scandinavia, April.

Juan Carlos Munoz / Two White Tailed Sea Eagle (Haliaeetus albicilla) fighting in acrobatic flight as Raven (Corvus corax) looks on. Scandinavia, April. 5th, 2010 Euronatur Wildlife photographer competition.

Gerrit Vyn / Dall sheep (Ovis dalli) rams head butting, one behaviour by which males establish dominance during the Autumn mating season. Denali National Park, Alaska, USA

Andy Rouse / Two Common Zebra (Equus quagga) fighting. Masai Mara, Kenya.

Terry Whittaker / 2020VISION / Red deer (Cervus elaphus) stag chasing another during a fight, rutting season, Bushy Park, London, UK, October

Terry Whittaker / 2020VISION / Two Red deer (Cervus elaphus) stags fighting, rutting season, Bushy Park, London, UK, October

Terry Whittaker / 2020VISION / Two Red deer (Cervus elaphus) stags fighting, rutting season, Bushy Park, London, UK, October (This image may be licensed either as rights managed or royalty free.)

Terry Whittaker / 2020VISION / Two Fallow deer (Dama dama) bucks during fight, rutting season, Richmond Park, London, UK, October (This image may be licensed either as rights managed or royalty free.)

Markus Varesvuo / Horned / Slavonian grebe (Podiceps auritus) two individuals fighting in water, Finland May

Terry Whittaker / 2020VISION / Konik horse (Equus caballus) two stallions fighting, Wicken Fen, Cambridgeshire, UK, June

Terry Whittaker / 2020VISION / Konik horse (Equus caballus) two stallions fighting, Wicken Fen, Cambridgeshire, UK, June

Terry Whittaker / 2020VISION / Konik horse (Equus caballus) herd grazing with two stallions interacting, Wicken Fen, Cambridgeshire, UK, June 2011

Radomir Jakubowski / Two Muskox (Ovibos moschatus) in landscape, Dovrefjell national park, Norway, September

Anup Shah / Adolescent male Lions (Panthera leo) play fighting, Masai Mara National Reserve, Kenya, March

Dave Watts / Eastern grey kangaroo (Macropus giganteus) two males boxing, Australian Capital Territory, Australia, December

Andrew Parkinson / Whooper swan (Cygnus cygnus) adult aggressively chasing another, UK visitor between November and March. Lancashire, UK, October.