Skin

A remarkable feature of cephalopods is their complex and beautiful skin. Many species can rapidly change their appearance quickly. This feature is called Rapid Adaptive Coloration. It is used for camouflage and communication.

The most important elements in the skin are chromatophores. They are tiny sacs of pigment surrounded by muscles that are under nervous control, so they can rapidly expand and contract. The color of the pigment may be red, brown or yellow, depending on development and species.

In many species, the chomatophores overlie reflective tissue called iridophores, which reflect light. Some species also have permanent white patches just below the iridophores called leucophores.

Recent experiments have shown that cephalopods control their body pattern visually. For camouflage, they view their surroundings and quickly process the visual information. Then, the central brain sends neural signals throughout the skin to chromatophores and iridophores to produce the appropriate body pattern. This entire process can take less than 200 milliseconds – faster than a blink of the eye!

In addition to the colorful body patterns, octopuses and cuttlefishes can morph their skin into three-dimensional shapes to enhance camouflage called papillae. No other animal on the planet can do this.