One naturalist insisted flamingos were pink to hide against the dawn sky
Abbott Thayer correctly explained countershading, the pale belly and dark back that flatten an animal's shape. Then he overreached, claiming all animal colour was camouflage, even the flamingo's blazing pink. Theodore Roosevelt mocked the idea, and the debate shows how many jobs colour really does in nature.
An animal's colour is simply how its surfaces reflect or emit light, yet evolution has put it to many uses. Camouflage conceals; bright patterns can advertise cleaning services to other species, announce sexual readiness, or copy a dangerous neighbour's warning dress. Sudden flashes may startle an attacker, and zebras might confuse predators through motion dazzle. Some pigments guard against sunburn, some frogs shift shade to manage heat, and some colours are accidents: blood looks red only because oxygen-carrying haem happens to be red.
Colour is made in several ways, often combined. Pigment particles such as freckles give direct colour, while chromatophores are cells whose pigment can be spread or bunched under hormonal or nervous control, and in fish they may react straight to light, temperature or chemistry. Tiny structures in butterfly scales and bird feathers produce iridescence, and squid and some deep-sea fish make their own light. Aristotle noticed octopuses matching their surroundings, and in 1665 Robert Hooke peered at peacock feathers in Micrographia, showing their shimmer was structural because wetting them made it vanish.
Darwin's 1859 theory explained colour as a survival edge: slightly better-hidden grouse leave more young, since hawks hunt by sight. Henry Walter Bates, studying Amazon butterflies in 1863, found harmless species imitating distasteful ones, now called Batesian mimicry. Edward Poulton's 1890 book backed female choice as the driver of showy male plumage, introduced frequency-dependent selection and coined aposematism for warning colours in animals from skunks to wasps. Frank Beddard's critical 1892 reply drew Poulton's fire.
Thayer's 1909 book, finished by his son Gerald, rightly stressed how common concealment is but spoiled the case by treating it as colour's only purpose. Hugh Cott's 500-page Adaptive Coloration in Animals, published in wartime 1940, offered a sober survey with hundreds of examples and emphasised maximum disruptive contrast, the principle behind military camouflage patterns.
Source: Animal coloration
