A brilliantly-coloured Oriental Sweetlips fish (Plectorhinchus vittatus) waits while two boldly-patterned Cleaner fish pick parasites from its skin. The spotted tail and fin pattern of the Sweetlips signals sexual maturity; the behaviour and pattern of the Cleaner fish signal their availability for cleaning service, rather than as prey

Peacock butterfly is a cryptic leaf mimic when its wings are closed

Peacock butterfly displays startling eyespots when its wings are open; they also distract attacks away from the body. This insect has survived a bird's attack on the eyespot on the right hindwing

Red Underwing moth is cryptic and disruptively patterned at rest

Red Underwing moth's startling underwing flash when disturbed

The Zebra's bold pattern may momentarily confuse chasing lions: a dazzle defence

Animal colour (or coloration) is produced by light reflecting from an animal's surface. The ways animals produce colours include pigments, chromatophores and other structures, and bioluminescence.

Since sight is usually so important to animals, and is so often used by predators as a long-range way to find prey, an animal's colour must serve one or more functions. These functions, such as finding prey, or evading capture, or finding a mate, are absolutely essential for life and survival. Therefore, animal colour is determined by natural selection because it affects the survival of animals and their offspring.