Cephalopods (squid, octopus, cuttlefish) can change the color of their skin by contracting/relaxing muscles controlling pigment granules in their chromatophore organ. Chromataphores can be classified into subclasses based on colors- specifically for this blog post we will talk about iridophores (reflective/iridescent) ones.
A recent study found that electrical stimulation of the nerves in the skin of squid change the reflectance/color of the iridophores ranging across the color spectrum. But did you know- SQUID ARE COLORBLIND?! So why do they display so many beautiful colors?
It’s a question scientists ponder all the time- how do squid and octopus see a color in black and white which is actually red and brown- and their skin turns the perfect color that we see? It’s magic I guess (or an awesome evolutionary feat).
The iridophores are made up of complex stacked plates that cause the interference with the reflectance of light. To learn more about iridophores in the skin of squid, scientists took advantage of a dead longfin inshore squid’s skin. The scientists traced the nerves of the skin and stimulated them electrically- see what they saw- CLICK THE LINK BELOW:
The scientists found they could instigate progressive changes in skin color from reddish (which is the color when the chromatophores are at-rest) all the way across the color spectrum to blue. Iridophores were found to change much more slowly than the quick changes seen in most other chromatophores.
Yet again, the cephalopod family adds something new to the list of why I love them. Here’s another cool video I found on YouTube pertaining to chromatophores in squid skin- ENJOY!