stylistic:style_transfer, linguistic:translation
Variable coloration by chromatophores

Chromatophores are special pigment-containing cells that may change their size, but more often retain their original size but allow the pigment within them to become redistributed, thus varying the colour and pattern of the animal. Chromatophores may respond to hormonal and/or neurobal control mechanisms, but direst responses to stimulation by visible light, UV-radiation, temperature, pH-changes, chemicals, etc. have also been documented. The voluntary control of chromatophores is known as metachrosis. For example, cuttlefish and chameleons can rapidly change their appearance, both for camouflage and for signalling, as Aristotle first noted over 2000 years ago:

The octopus... seeks its prey by so changing its colour as to render it like the colour of the stones adjacent to it; it does so also when alarmed.

When cephalopod molluscs like squid and cuttlefish find themselves against a light background, they contract many of their chromatophores, concentrating the pigment into a smaller area, resulting in a pattern of tiny, dense, but widely spaced dots, appearing light. When they enter a darker environment, they allow their chromatophores to expand, creating a pattern of larger dark spots, and making their bodies appear dark. Amphibians such as frogs have three kinds of star-shaped chromatophore cells in separate layers of their skin. The top layer contains ' xanthophores ' with orange, red, or yellow pigments; the middle layer contains ' iridophores ' with a silvery light-reflecting pigment; while the bottom layer contains ' melanophores ' with dark melanin.