Rod Williams / Female Geoffroy's cat {Felis geoffroyi}. Rare melanistic form. Captive.

Lynn M Stone / Melanistic (black form) leopard snarling, often called black panther (captive)

Pete Oxford / Jaguar (Panthera onca), melanistic dark color phase known as a black panther, Yasuni National Park, Amazon Rainforest, Ecuador

MYN / Paul Marcellini / Melanistic Mosquitofish (Gambusia affinis holbrooki) Big Cypress National Preserve, Florida, USA, February. meetyourneighbours.net project

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, snarling, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Michael Quinton / Arctic Ground Squirrel (spermophilus parryii) melanistic dark coloring, Alaska

Stephen Dalton / Peppered moth [Biston betularia} normal grey form and dark melanistic form. Dark form is better camouflaged in areas of pollution where lichen is absent, UK

Andy Rouse / Melanistic Jaguar (Panthera onca) in rainforest, captive, Belize

Roger Powell / European rabbits {Oryctolagus cuniculus} young black (melanistic) and normal colour form, Dornoch, Sutherland, Scotland, UK

Roger Powell / European rabbits {Oryctolagus cuniculus} two young black (melanistic) rabbits at burrow entrance, Dornoch, Sutherland, Scotland, UK

Roger Powell / European rabbit {Oryctolagus cuniculus} young black (melanistic) rabbit alert to danger soon after emerging from burrow, Dornoch, Sutherland, Scotland, UK

Roger Powell / European rabbit {Oryctolagus cuniculus} young black (melanistic) rabbit alert to danger soon after emerging from burrow, Dornoch, Sutherland, Scotland, UK

Doug Perrine / Hawaiian / Pantropical / Long snouted / Gray's spinner dolphins (Stenella longirostris longirostris) Kona Coast, Big Island, Hawaii (Central Pacific Ocean) with albinistic (white) calf at bottom

Robert Valentic / Eastern brown snake {Pseudonaja textilis} melanotic female in pre-strike posture, Bundaburg, Queensland, Australia

Francis Abbott / Lilford's wall Lizards (Podarcis lilfordi) melanistic black form only found on the Isla del Aire, Menorca, Spain

Francis Abbott / Lilford's wall Lizard (Podarcis lilfordi) melanistic black form only found on the Isla del Aire, Menorca, Spain

Francis Abbott / Lilford's wall Lizard (Podarcis lilfordi) melanistic black form only found on the Isla del Aire, Menorca, Spain

Francis Abbott / Lilford's wall Lizard (Podarcis lilfordi) melanistic black form only found on the Isla del Aire, Menorca, Spain

Dave Bevan / Red kite (Milvus milvus) melanistic white variant, Wales, UK

Tony Phelps / Adder (Vipera berus) melanistic male on grass, Surrey, UK, April 2008

Tony Phelps / Adder (Vipera berus) melanistic male on grass, Surrey, UK, April 2008

Tony Phelps / Adder (Vipera berus) melanistic male, Surrey UK, April 2008

Tony Phelps / Head of Moroccan / Egyptian cobra {Naja haje} legionis colour morph, juvenile, captive, occurs North Africa

Tony Phelps / Moroccan / Egyptian cobra {Naja haje} legionis colour morph, juvenile, captive, occurs North Africa

Tony Phelps / Melanistic Rhombic skaapstecker {Psammophylax rhombeatus} Western Cape, South Africa

Nature Production / Japanese Ratsnake (albino) {Elaphe climacophora} Japan

Tony Phelps / Adder melanic / black female {Vipera berus} New Forest, Hampshire, UK

Tony Phelps / Adder males fighting, melanic / black and normal colours {Vipera berus} Dorset, UK

Dave Watts / Leopard Black / Melanistic Panther) {Panthera pardus} looking startled, Captive

Pete Oxford / Black panther (Jaguar) {Panthera onca} captive, Amazonia, Brazil.

Dave Watts / Tawny Frogmouth, albino {Podargus strigoides} Tasmania, Australia

Michael Hutchinson / Viviparous lizard, melanistic morph {Lacerta vivipara} Somerset, UK.

Tony Phelps / Slow worm {Anguis fragilis} pink morph male, Purbeck, Dorset, UK

Lynn M Stone / Melanistic (black form) leopard (Panthera pardus) often called Black panther. Captive.

Bristol City Museum / Peppered moth {Biston betularia} specimens: melanic dark form is better camouflaged in urban areas and has been dominant in UK but as air quality has improved over past decades, the lighter form is ma...

Pete Oxford / Jaguar (Panthera onca), melanistic dark color phase known as a black panther, Yasuni National Park, Amazon Rainforest, Ecuador

Pete Oxford / Jaguar (Panthera onca), melanistic dark color phase known as a black panther, yawning, Yasuni National Park, Amazon Rainforest, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther peeking from behind a tree, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, snarling, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Jaguar (Panthera onca) melanistic individual, also called a black panther, walking, Yasuni National Park, Amazon, Ecuador

Michael Quinton / Arctic Ground Squirrel (spermophilus parryii) melanistic dark coloring, Yukon, Canada

Michael Quinton / Arctic Ground Squirrel (spermophilus parryii) melanistic dark coloring, Alaska

Eric Baccega / Head portrait of female Jaguar (Panthera onca) black melanic form, captive.

Graham Eaton / Black Pheasant (Phasianus colchicus) melanistic variant form of common Pheasant, female, Wirral, UK, January

Graham Eaton / Black Pheasant (Phasianus colchicus) melanistic variant form of common Pheasant, male, Wirral, UK, June

Jabruson / Albino Vervet monkey (Chlorocebus / Cercopithecus aethiops) reaching out through cage, Kigali, Rwanda

Jabruson / Albino Vervet monkey in cage (Chlorocebus / Cercopithecus aethiops) Kigali, Rwanda

Constantinos Petrinos / Black melanistic Spine cheeked anemonefish living in Haddons sea anemone. Sulawesi Indonesia

Constantinos Petrinos / Black melanistic Spine cheeked anemonefish living in Haddons sea anemone. Sulawesi Indonesia