Shattil & Rozinski / Juvenile American black bear (Ursus americanus), brown phase, looking for food in a car, Denver, Colorado, USA, July.

SINCLAIR STAMMERS / Phase contrast photomicrograph of Blue green alga / Cyanobacteria (Spirulina platensis) each algal filament or Trichome is 5 microns in diameter.

Jane Burton / Spotted seahorse {Hippocampus kuda} light colour phase, note eyes rotating independantly from each other, captive, from Indo-Pacific

TOM MANGELSEN / Stoat / Ermine in winter coat by wood pile (Mustela erminea) Grand Teton NP, USA

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

Constantinos Petrinos / Ribbon eel in male blue phase {Rhinomuraena quaesita} Sulawesi, Indonesia - species is hermaphrodite changing sex from male to female; juveniles are black, male is blue underneath , and final female p...

Heather Angel / Bloody bellflower (Nesocodon mauritianus), female phase with red nectar surrounding stigma. Native to Mauritius. Cultivated at Kew Gardens, London, England, UK.

Heather Angel / Chinese meadow-rue (Thalictrum delavayi) flowers. Male phase below with stigmas hanging below immature stigmas, female phase above after stamens have fallen. Sha Chong He River Valley, near Danba, Sic...

Richard Robinson / Yellowtail coris (Coris gaimard) also known as the African Coris in it's female phase at Matthew Island a volcanic Island in disputed territory between New Caledonia (France) and Vanuatu in the South...

Terry Whittaker / Jungle / Reed cat ( Felis chaus) captive, occurs in N Africa, N Asia, Captive. Black phase.

Philippe Clement / Raccoon dog (Nyctereutes procyonoides) resting under tree trunk in forest, white color phase, Germany, May. Captive.

Dave Watts / Two dark phase Eastern quolls (Dasyurus viverrinus) feeding at night, Ben Lomond National Park, Tasmania, Australia.