FAQ
A contribution of The Cephalopod Page
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Hi James, I viewed your Cephalopod page because I recently saw on TV that Cephalopods can change their color quickly and intensively. Now I'm looking for someone who can give me examples, e.g. how fast they can change colors, what kind of changes they do etc. Moreover I'm interested in HOW they do it. Do you know somebody who can tell me about the biochemistry of color changes of Cephalopods? Thank you for your help. |
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| Dear Michael,
Did you see 'Incredible Suckers' - if so, the TV special should give you an idea of what is possible and how fast they can change colors. If not... the kinds of changes depend on the species - for instance, my deep-sea octopuses only become slightly darker or lighter while Octopus horridus can mimic the vivid coloration of a lionfish (lionfish are poisonous) and some schooling species like Sepia are thought to communicate with color patterns. Cephalopods have been called the chameleons of the sea. This is an insult as they can change color much faster and produce a wider variety of complex patterns than anything else on land or the sea. (See the book by Hanlon and Messenger). Cephalopods primarily change colors by using chromatophores. Imagine a small clear balloon that is filled with ink. Now imagine five or so small muscles attached to the balloon and radiating away from it. When the muscles are relaxed, the surface area of the sac is small and the color is not expressed. When the muscles contract the surface area becomes much greater and we see the color. What I have just described is a chromatophore and they are responsible for colors such as yellow, orange, brown, red, blue and black depending on the ink. All of this is under the control of their advanced nervous system. Although cephalopods are known for their large brain, they also have a lot of local control, much more than any vertebrate. For example, 2/3 of the nerves in an octopus are in the arms and each sucker segment in arm has several sets of ganglia. All this local processing of information makes cephalopods very fast. Cephalopods also have iridocytes which differentially reflect light. They can change texture and create ink decoys as well. Dr. James Wood |