Animal colour comes from a combination of pigments (like melanin and carotenoids) and structural mechanisms, and serves a range of purposes including camouflage, warning display, thermoregulation and mate attraction — though not every colour pattern has a single agreed explanation.
A molecule in the tissue absorbs some wavelengths of light and reflects others — the reflected wavelengths are the colour seen. Chlorophyll, carotenoids and melanin are the most common examples.
Common misconception: Not every vivid natural colour is a pigment — several of the most striking blues and greens in animals are structural colour instead, which looks similar but works completely differently.
Microscopic physical structures — ridges, layers or particles smaller than the wavelength of light — interfere with light waves so that only certain wavelengths are reflected back. No pigment is involved at all.
Common misconception: A structurally-coloured feather or scale ground into powder loses its colour completely, because grinding destroys the microscopic structure that produced it.
Melanin is one of the most widespread animal pigments, producing colours from pale yellow through brown to black, and is also linked to functions such as UV protection and structural strength in feathers and hair.
Animals · confidence: high
Carotenoid pigments, which animals generally obtain from their diet rather than producing themselves, are responsible for many red, orange and yellow colours in animals such as flamingos and various fish.
Animals · confidence: high
Structural colour — colour produced by microscopic physical structures rather than pigment — is well documented across birds, butterflies, beetles and some fish, and is the primary mechanism behind most blue and iridescent animal colouration.
Animals · confidence: high
Not every animal colour or pattern has a conclusively established adaptive purpose — some are the incidental result of pigment biochemistry rather than a specific evolved function.
Animals · confidence: medium
Applies to specific cases; many well-studied cases do have established or strongly supported purposes.
Frequency and rarity claims above are scoped to a specific domain, geography or taxonomic group — none are presented as a single universal ranking. See methodology.