Jack Dykinga / Rain spattered inter-locking palm leaves create a design of pattern and colour in the tropical rainforest. Osa Peninsula, Costa Rica

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration. Adams River, British Columbia, Canada, October.

SCOTLAND: The Big Picture / Red deer (Cervus elaphus) stags sparring during rutting season, February.

Tony Wu / Malabar pied hornbills (Anthracoceros coronatus) pair engaged in an argument, with their beaks locked together and one bird flipping over the other, Yala National Park, Sri Lanka

Alex Mustard / A split level photo of group of Sockeye salmon (Oncorhynchus nerka) fighting their way upstream as they migrate back to the river of their birth to spawn, trees showing autumnal colours. Adams River,...

Michel Roggo / Dead Sockeye / Red Salmon (Oncorhynchus nerka) after spawning migration. Adams River, British Columbia, Canada, October.

Michael Hutchinson / Male Moorhens (Gallinula chloropus) fighting with clawing feet locked together, Gloucestershire, UK

Steven Kazlowski / Group of Wild Grey wolves {Canis lupus} with pair locked together after mating, Denali National Park, Alaska, USA

Michio Hoshino / Alaska Moose (Alces alces gigas) two skulls with antlers locked together in stream bed, males probably became fatally entangled while fighting, Alaska

Jim Brandenburg / Canada Jay (Perisoreus canadensis) perching on the antlers of two Moose (Alces alces andersoni) who locked antlers in battle and died together, Michigan

Andy Sands / Slime mould (Physarum sp.) group of sporangia fused together, Hertfordshire, England, UK. October. Focus stacked.

George Sanker / Wild turkey (Meleagris gallopavo) toms fighting chest to chest with beaks locked together, Acadia National Park, Maine, USA. March.