Anup Shah / Southern / Masai giraffe (Giraffa camelopardalis tippelskirchi) males dominance mating, Masai Mara National Reserve, Kenya. February

Anup Shah / Male lions playing (Panthera leo) Masai Mara, Kenya, East Africa. Homosexual?

Graham Eaton / Mandarin Duck (Aix galericulata) drakes exhibiting homosexual behaviour, Wirral, UK, April

Paul Hobson / Mallard {Anas platyrhynchos} homosexual mating, Glos, UK

Pete Oxford / Male lions play copulating. Savuti, Botswana, Southern Africa

Emanuele Biggi / Two Yellow baboon (Papio cynocephalus) males exhibiting homosexual behaviour, showing the typical 'double foot clasp' mounting posture. This behavior is still studied, but it's mainly due to domi...