An Octopus can See with its Skin

A new study reveals that Octopus are able to see with their skin.

This will blow your geek mind. And why has that not been discovered earlier? A new study by UC Santa Barbara in California that an octopus can see with his skin. The skin of the California two-spot octopus (Octopus bimaculoides) can sense light even without input from the central nervous system.

“Octopus skin doesn’t sense light in the same amount of detail as the animal does when it uses its eyes and brain,” said lead author Desmond Ramirez, a doctoral student in the Department of Ecology, Evolution and Marine Biology (EEMB). “But it can sense an increase or change in light. Its skin is not detecting contrast and edge but rather brightness.”

The animal does so by using the same family of light-sensitive proteins called opsins found in its eyes. This is a process not previously described for cephalopods. Desmond Ramirez and his co-author, Todd Oakley, an EEMB professor, dubbed the process Light-Activated Chromatophore Expansion (LACE).

According to Oakley, this new research suggests an evolutionary adaptation. “We’ve discovered new components of this really complex behavior of octopus camouflage,” said Oakley, who calls cephalopods the rock stars of the invertebrate world.

“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,” he explained. “So instead of completely inventing new things, LACE puts parts together in new ways and combinations.”

Octopuses are not the only marine mollusks whose skin can sense light, but scientists don’t know yet whether the skin of those other animals contains the light-sensitive opsins. If they do, Ramirez wants to understand how these two groups are related.

“Do they all come from the same ancestral source or did they evolve multiple times?” he asked. “What kind of behaviors do the different groups share and what kind of behaviors does the skin sensing light underlie?”

The findings of the UCSB scientists will has been published in the Journal of Experimental Biology.