I have this alien race of amoeba-like creatures about the size of humans with the ability to morph their shape and move by constantly making and dissolving muscles by manipulating their membrane and bursting capillaries.

But these muscles cannot be permanent and making smaller ones is much harder for them than making bigger less specific ones. And this is a problem because their language is mostly based on color and how color changes on the body of an individual.

And other animals do this through muscularly manipulating chromatophores but since these muscles would to hard to generate in these creatures what would be a viable mechanism for rapid color changing like in cuttlefish?

(I had an idea on doing it through oxidizing and de-oxidizing vanadium but I'm not to sure on how fast it can be done and if their are enough colors from it to form a complex language)

  • $\begingroup$ cuttlefish also use chromatophores, as well as several other structures also controlled by tiny muscles. $\endgroup$
    – John
    May 20, 2018 at 2:14
  • $\begingroup$ @John yeah but I'm asking for specifically non muscular ways of doing it $\endgroup$
    – Amoeba
    May 20, 2018 at 3:25

1 Answer 1


You could have them change colors rapidly by having the creatures coated in a thin film, or with a color communication organ comprised of a thin film. They can change the thickness of the film. The color of the film will depend on its thickness.

colors of a thin film http://soapbubble.wikia.com/wiki/Color_and_Film_Thickness

More on the same topic from wikipedia: https://en.wikipedia.org/wiki/Thin-film_interference

Thin-film interference is a natural phenomenon in which light waves reflected by the upper and lower boundaries of a thin film interfere with one another, either enhancing or reducing the reflected light. When the thickness of the film is an odd multiple of one quarter-wavelength of the light on it, the reflected waves from both surfaces interfere to cancel each other. Since the wave cannot be reflected, it is completely transmitted instead. When the thickness is a multiple of a half-wavelength of the light, the two reflected waves reinforce each other, increasing the reflection and reducing the transmission. Thus when white light, which consists of a range of wavelengths, is incident on the film, certain wavelengths (colors) are intensified while others are attenuated. Thin-film interference explains the multiple colors seen in light reflected from soap bubbles and oil films on water.

As you can see from the top image, the films involved are very thin. The thickness change would be only nanometers to produce any color.

How could your creatures manipulate the thickness of a film? Maybe the film is a bubble-like communication structure and they can precisely control the gas pressure inside the bubble and so the thickness. Maybe the film coats the creature and they can stretch and relax it, altering its thickness and so its color.

  • $\begingroup$ This could be problematic as a communication method as the colour would change depending on viewing angle, so all the amoeba could actually do is modulate the periodicity of a rainbow pattern on their surface. That would be pretty but I’m having a hard time figuring out how you might use it to communicate (perhaps part of the alien charm?) $\endgroup$
    – Joe Bloggs
    May 20, 2018 at 11:16
  • $\begingroup$ @JoeBloggs: communication by visual cues is usually assumed to be omnidirectional because that is how it usually works for us. Sound and odor communication is also usually omnidirectional. Everybody can see, everybody can hear, everybody can smell what you are communicating. But your observation is a very cool one - if only the recipient at the correct angle can see your message, it is like whispering in her ear. $\endgroup$
    – Willk
    May 20, 2018 at 16:00
  • $\begingroup$ my point was that thin films always display rainbows, so unless the information is encoded in a very clever way it’s going to be nigh on impossible to work out what the message is, but just because I can’t think of a way to encode it doesn’t mean one doesn’t exist! $\endgroup$
    – Joe Bloggs
    May 20, 2018 at 16:25
  • $\begingroup$ It probably does exist, it just might take a very long time to say anything, as the simplest solution is to increase the length of your "words" to allow there's creatures to have a large and difficult to misinterpret language $\endgroup$
    – Pliny
    May 21, 2018 at 17:07

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