Michio Hoshino / Polar Bear (Ursus maritimus) males fighting, Churchill, Manitoba, Canada

Bence Mate / Great egrets {Ardea alba} and Grey herons {Ardea cinerea} fighting over fish, Pusztaszer, Hungary

Markus Varesvuo / Dippers (Cinclus cinclus) fighting on ice over feeding territory, Kuusamo, Finland, February.

Valeriy Maleev / Male Saiga antelope (Saiga tatarica) rutting in winter, 'The Black Lands' National Park, Kalmykia, Russia.