California Two-Spot Octopus Can 'See' Light with Its Camouflaging Skin

The octopus is a strange creature, able to change the color, pattern and even texture of its skin. Now, scientists have discovered that the octopus can sense light with their skin.

In this latest study, the researchers examined the California two-spot octopus. They found that when the shone white light on the octopus's skin, the chromatophores there relaxed and the skin returned to its original color. This suggests that light sensors are connected to the chromatophores and this enables a response without input from the brain or eyes. This process, in particular, has been dubbed Light-Activated Chromatophore Expansion (LACE).

The scientists then tested the octopus's skin sensitivity across the spectrum by exposing it to different wavelengths of light from violet to orange. They found that chromatophore response time was quickest under blue light. The researchers also found that rhodopsin could be found in the skin. This protein is usually found in the eye.

We've discovered new components of this really complex behavior of octopus camouflage. It looks like the existing cellular mechanism for light detection in octopus eyes, which has been around for quite some time, has been co-opted for light sensing in the animal's skin and used for LACE, "said Todd Oakley, one of the researchers, in a news release. "So instead of completely inventing new things, LACE puts parts together in new ways and combinations."

Octopuses aren't the only marine mollusks whose skin can sense light. However, scientists don't know yet whether the skin of other animals contains the light-sensitive opsins. If they do, though, the researchers hope to find out how the two groups are related. Currently, the scientists plan to conduct new experiments to seek the answers to these questions.

The findings are published in the Journal of Experimental Biology.

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