Petra Wegner / Cavalier King Charles Spaniels, ruby and tricolour, sitting in snow.

Konrad Wothe / Eclectus Parrot (Eclectus roratus) courtship behaviour in rainforest, Cape York Peninsula, North Queensland, Australia, captive

Konrad Wothe / Eclectus Parrot (Eclectus roratus) pair in rainforest, female on right, Cape York Peninsula, North Queensland, Australia, captive

Aflo / Group portrait of three Chihuahua puppies, sitting on white towels

Petra Wegner / Five Cavalier King Charles Spaniel sitting, black-and-tan, tricolour, blenheim and ruby coated, sitting in autumn leaves

Petra Wegner / Two Cavalier King Charles Spaniels, blenheim and tricolour coated, sitting wearing reindeer antlers

Petra Wegner / Two Miniature Schnauzers, black-silver and pepper-and-salt coated, sitting in autumn foliage

Petra Wegner / Cavalier King Charles Spaniel, ruby, black-and-tan, tricolour and blenheim, sitting in line on beach, panting

Petra Wegner / Lion-maned Dwarf Domestic Rabbits, 13 weeks, Dwarf Rabbit, and Satin Lop-eared Dwarf Rabbit, 8 weeks

Philippe Clement / Bluebells (Hyacinthoides non-scripta) white morph amongst blue flowers, Belgium

Michael Hutchinson / Bluebells (Hyacinthoides non-scripta); white form next to normal blue form, North Somerset, UK

Jane Burton / Domestic cat (Felis catus) 8-week-old kittens

Kim Taylor / Peppered moth {Biston betularia} normal and melanic forms on birch trunk. UK.

Rolf Nussbaumer / Vermilion flycatcher pair at nest feeding chicks, Texas, USA {Pyrocephalus rubinus}

Rolf Nussbaumer / Common buzzard, white morph {Buteo buteo} Switzerland.

Rolf Nussbaumer / Fox squirrel, black form {Sciurus niger} Texas, USA.

PREMAPHOTOS / White lipped snails on moss (Cepaea hortensis) showing variation in pattern on shell within the species, UK.

Tom Vezo / Grey wolves showing fur colour variation. (Canis lupus)

Tony Phelps / Adder {Vipera berus} melanic / black form female with normal morph young. Dorset, UK

Mark Carwardine / Juvenile Green tree python {Chondopython viridis} captive

Ernie Janes / Corn snakes (Pantherophis guttatus) showing two colour forms, captive

Petra Wegner / Eurasiers lying.

Petra Wegner / Cavalier King Charles Spaniels, ruby and black-and-tan.

Petra Wegner / Cavalier King Charles Spaniels, ruby and black-and-tan.

Petra Wegner / Cavalier King Charles Spaniels, ruby and black-and-tan.

Petra Wegner / Chinese Crested Dogs, hairless puppies, 4 1/2 months / bitch.

Petra Wegner / Australian Shepherd puppy, 19 weeks, and Border Collie puppy, 13 weeks.

Petra Wegner / Chinese Crested Dogs, hairless puppies, 4 1/2 months / bitch.

Petra Wegner / British Shorthair Cats, kittens, cinnamon and fawn, 3 months.

Petra Wegner / Australian Shepherd puppy, 19 weeks, and Border Collie puppy, 13 weeks.

Petra Wegner / Australian Shepherd, puppy, 19 weeks, and Border Collie, puppy, 13 weeks.

Petra Wegner / Chinese Crested Dogs, couple, hairless and powderpuff varieties.

Petra Wegner / Cavalier King Charles Spaniel puppies, tricolour, blenheim and black-and-tan.

Petra Wegner / Cavalier King Charles Spaniel puppies tricolour, blenheim and black-and-tan.

Petra Wegner / Cavalier King Charles Spaniel puppies, tricolour, blenheim, black-and-tan

Petra Wegner / Chinese Crested Dogs, hairless and powderpuff puppies, 4 months and 9 weeks on small sofa.

Petra Wegner / Cavalier King Charles Spaniels, blenheim and tricolour.

Petra Wegner / Cavalier King Charles Spaniels with puppy, blenheim and tricolour.

Petra Wegner / Cavalier King Charles Spaniel puppies; blenheim, black-and-tan, 4 months.

Petra Wegner / Cavalier King Charles Spaniel puppies, tricolour and blenheim, 7 weeks.

Petra Wegner / Cavalier King Charles Spaniel,puppies, tricolour and blenheim, 7 weeks.

Petra Wegner / Cavalier King Charles Spaniel, bitch with puppy, blenheim and tricolour.

Petra Wegner / Cavalier King Charles Spaniel puppies, blenheim and tricolour, 7 weeks.

Konrad Wothe / Eclectus Parrot (Eclectus roratus) mating, rainforest, Cape York Peninsula, North Queensland, Australia, captive

Robert Thompson / Elder-flowered orchid (Dactylorhiza sambucina) with yellow and purple flowers, Apennine Mountains, Italy, May

Loic Poidevin / Ruff (Philomachus pugnax) two rival males displaying on coast, Varanger, Norway, May

Loic Poidevin / Ruff (Philomachus pugnax) two males displaying, back to back, Varanger, Norway, May

Loic Poidevin / Ruff (Philomachus pugnax) males displaying, Varanger, Norway, May

Loic Poidevin / Ruff (Philomachus pugnax) males displaying, Varanger, Norway, May

Aflo / Group portrait of three Chihuahua puppies, sitting on white towels

Aflo / Portrait of two Chihuahua puppies, sitting

Charlie Summers / Two Tawny eagles (Aquila rapax) one in light phase and the other in dark phase, perched on tree branch, Kgalagadi TB Park of South Africa

Petra Wegner / British Longhair Cats, tomcats, black and red coated (Highlander, Lowlander, Britannica) sitting on large log, with autumn foliage

Petra Wegner / White and Golden-ticked British Shorthair Cats, standing on netted balcony, looking out

Petra Wegner / Two Miniature Schnauzers, black-silver and pepper-and-salt coated, lying in autumn foliage

Petra Wegner / Two Miniature Schnauzers, black-silver and pepper-and-salt coated, lying in autumn foliage

Petra Wegner / Two Cavalier King Charles Spaniels, black-and-tan and ruby, sitting in autumn leaves

Petra Wegner / Tibetan Terriers, two adults with with puppy, aged 4 months, group portrait sitting

Petra Wegner / Three Cavalier King Charles Spaniel, two adults, blenheim and tricoloured coated, with juvenile bitch, aged, 7 months, tricoloured

Petra Wegner / Two Tibetan Terriers, double portrait sitting together

Petra Wegner / Two Cavalier King Charles Spaniels, sitting together, black-and-tan and ruby coated

Petra Wegner / Two Cavalier King Charles Spaniels, double portrait standing together, black-and-tan and ruby coated

Petra Wegner / Two Texel Guinea Pigs, choco-white and choco-red-white long haired

Petra Wegner / Two Tibetan Terriers, double portrait sitting together

Petra Wegner / Two Bengal Cats, Snow Bengal and Marbled Bengal coated, sitting together

Petra Wegner / Three Cavalier King Charles Spaniel, group portrait, blenheim, ruby and tricolour coated, sitting

Petra Wegner / Double portrait of Texel Guinea Pig, choco-white long haired, and Lunkarya Guinea Pig, with pink eyes

Petra Wegner / Two Tibetan Terriers, double portrait standing together

Petra Wegner / Three Cavalier King Charles Spaniels, sitting together, black-and-tan and ruby coated

Petra Wegner / Tibetan Terrier with puppy, aged 4 months, double portrait, sitting

Petra Wegner / Two Sacred Cats of Burma / Birman, blue-tabby-point and chocolate-tabby-point touching noses, standing on a log in snow, with picket fence behind

Petra Wegner / Two Bengal Cats, Snow Bengal and Marbled Bengal coated, sitting together

Petra Wegner / Tibetan Terrier with puppy, aged 4 months, double portrait, sitting

Petra Wegner / Two Bengal Cats, Snow Bengal and Marbled Bengal coated, sitting together

Petra Wegner / Two Texel Guinea Pigs, choco-white and choco-red-white long haired

Petra Wegner / Cavalier King Charles Spaniels, ruby coated, sitting with black-and-tan puppy aged 8 months

Petra Wegner / Two Texel Guinea Pigs, choco-white and choco-red-white long haired

Petra Wegner / Cavalier King Charles Spaniel, double portrait of bitch blenheim coated, and juvenile bitch, aged, 7 months, tricoloured

Petra Wegner / Cavalier King Charles Spaniel, portrait of bitch, blenheim coated, and puppy aged 7 months, tricoloured

Petra Wegner / Two Miniature Schnauzers, black-silver and pepper-and-salt coated, lying in autumn foliage

Petra Wegner / Two Miniature Schnauzers, black-silver and pepper-and-salt coated, sitting in autumn foliage

Petra Wegner / Two Guinea Pigs (Cavia porcellus) white/black and tan short coated, in wooden feeding rack, on garden lawn

Petra Wegner / Two Guinea Pigs (Cavia porcellus) white/black and tan short coated, on garden lawn feeding on piece of apple.

Petra Wegner / Two Guinea Pigs (Cavia porcellus) white/black and tan short coated, on garden lawn feeding on piece of apple.

Aflo / N-18206 Two Cosmos flowers, Japan.

Robert Thompson / Dark arches moth (Apamea monoglypha) two adults on tree bark showing different colouration, Castlewellan Forest Park, County Down, Northern Ireland, UK, July .

Stephen Dalton / Oriental fire-bellied toads (Bombina orientalis) in water, controlled conditions

Stephen Dalton / Snake's head fritillaries (Fritillaria mealagris) flowering in meadow, both purple and white flower types, UK

Stephen Dalton / Orb weaver spider {Agalenatea redii} two colour forms on vegetation, UK, Araneidae

Philippe Clement / Domestic sheep (Ovis aries) ewe with two lambs, one white and one black, Texel, the Netherlands

Tim Martin / Fallow deer stags (Dama dama), one white, grazing. New Forest National Park, Hampshire, UK. January 2008.

Philippe Clement / Six Common whelk (Buccinum undatum) shells, Normandy, France

Philippe Clement / Six Common whelk (Buccinum undatum) shells, Normandy, France

GEORGETTE DOUWMA / Lyretail anthias / Goldie (Pseudanthias squamipinnis) male with 'harem' of females. Red Sea, Egypt.

Philippe Clement / Yellow brain fungus (Tremella mesenterica) in yellow and colourless form, Belgium

Philippe Clement / Yellow brain fungus (Tremella mesenterica) in yellow and colourless form, Belgium