Danny Green / Mountain Hare (Lepus timidus) resting with ears back, Scotland, March. Highly Commended in the Animal Portrait Category of the BWPA Competition 2015.

Alex Hyde / Mountain hare (Lepus timidus), Cairngorms National Park, Scotland. January.

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) flapping ears, Botswana

Alex Hyde / Lined Leaf-tailed Gecko {Uroplatus lineatus} showing darker nocturnal colouration, camouflaged amongst dead palm fronds. Masoala Peninsula National Park, north east Madagascar.

Luiz Claudio Marigo / Meeting of waters of the River Solimoes and darker River Negro, Amazonas, Brazil. Rio

Mike Read / Barn owl, darker continental form {Tyto alba} captive UK

Emanuele Biggi / Cone-head katydid (Copiphora cornuta) on darker coloured leaf, Peru

Alex Mustard / Day octopus (Octopus cyanea) darker male reaching over and mates with a lighter female on the wreck of a barge. Gubal Island, Egypt. Strait of Gubal, Gulf of Suez, Red Sea.

Tui De Roy / Marine iguana (Amblyrhynchus cristatus), breeding male with smaller, darker females Floreana Island, Galapagos.

Angelo Gandolfi / Boat over on the Mediterranean sea with patches of darker waters showing beds of Mediterranean seagrass (Posidonia oceanica), Western Mediterranean Sea, Ibiza UNESCO World Heritage Site, Spain

Tony Wu / Humpback whale (Megaptera novaeangliae) engaged in courtship, whale in the foreground is the female. The darker one below is the male, Vava'u, Kingdom of Tonga. Pacific Ocean.

Alex Mustard / Smaller female Coral grouper (Cephalopholis miniata) flashes her submissive lighter colouration at larger, darker male. Jackson Reef, Strait of Tiran, Sinai, Egypt. Gulf of Aqaba, Red Sea.

Paul Harcourt Davies / Bee Orchid (Ophrys apifera var chlorantha) slighly darker yellow form, Italy, June.

Brent Stephenson / Immature white-capped albatross (Thalassarche cauta) (probably nearly two years old) in flight showing the underwing, darker bill pattern, and partial collar found in a bird of this age. Off Stewart I...

Brent Stephenson / Adult male Wrybill (Anarhynchus frontalis) peering up into the sky. Note the curved bill (always to the right) diagnostic of this species. Males have a broader breast band and darker forehead than fem...