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

Matthew Maran / Red fox (Vulpes vulpes) cub defending its kill,a large Brown rat (Rattus norvegicus) from another cub, North London, UK. August. Highly commended in the Behaviour : Mammals Category of the Wildlife Ph...

Alex Mustard / Split level image of Leather corals (Sarcophyton sp.) flourishing in shallow water close to uninhabited coral islands. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean...

Alex Mustard / Whale shark (Rhincodon typus) close to the camera with a golden trevally fish (Gnathanodon speciosus) and outline of another whale shark behind , in the plankton-rich green waters of La Paz bay, Baja...

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.

John Chan / Crenulated fiddler crab (Uca crenulata) waving its major claw at another crab, part of a courtship display, Southern California, USA, June.

John Shaw / Common giraffe (Giraffa tippelskirchi) bending to drink at a waterhole, with another standing on the opposite side of the pool reflected in the water. Klein Namutoni waterhole, Etosha National Park, N...

David Pattyn / Alpine marmot (Marmota marmota) carrying grass and other nesting material across snow to its nest while another one is on the lookout, Gran Paradiso National Park, Aosta Valley, Italy, April

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.

John Chan / Male California Least Tern (Sternula antillarum browni) courting a female, presenting a fish before chasing off another male, Huntington Beach, California, USA, May.

Claudio Contreras / Caribbean Flamingo (Phoenicopterus ruber) tending to newborn chick while another feed two day old chick, breeding colony, Ria Lagartos Biosphere Reserve, Yucatan Peninsula, Mexico, June, Finalist in t...