Aposematism

Aposematism is the practice by which an animal advertises to potential predators that it is not worth attacking or eating, a term drawn from Ancient Greek words for a warning sign. Poison dart frogs pair bright coloration with genuinely toxic skin alkaloids, skunks and zorillas advertise their chemical spray with black and white patterning, rattlesnakes give an acoustic warning with their rattle, tiger moths emit ultrasonic clicks to warn hunting bats, and honey badgers combine aggressive behavior with bold markings. Aposematic animals are deliberately conspicuous, the opposite of camouflage, which relies on blending in, and their signals are honest advertisements of a real defense, unlike deimatic displays, which merely bluff a predator without any defense behind them. Aposematism also underlies mimicry: in Batesian mimicry a harmless species copies a defended one deceptively, while in Mullerian mimicry several defended species resemble each other and share the cost of teaching predators to stay away.