If animals were superheroes, the octopus might have the most superpowers of them all. These remarkable creatures have eight dexterous arms, can shape-shift, instantly change color, communicate using light displays generated on their skin, taste things by touching them, squirt ink and use tools. They are some of the most intelligent invertebrates in the world, and can swim using jet propulsion.
As if all of these traits did not make the octopus amazing enough, scientists have now discovered yet another incredible superpower in its arsenal. The octopus can apparently also see with its skin, reports the Guardian.
New research by scientists at the University of California, Santa Barbara, has proven what has long been speculated: that octopus skin contains the same light-sensitive proteins (opsins) found in eyes, and that the skin is responsive to light independent of the animal's 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,” explained lead author Desmond Ramirez, in a press release. “But it can sense an increase or change in light. Its skin is not detecting contrast and edge, but rather brightness.”
For the study, researchers removed patches of skin from 11 hatchling and adult bimac octopi (Octopus bimaculoides), mounted them onto petri dishes and used light-emitting diodes to shine light of different wavelengths onto the preparations. Sure enough, the skin's chromatophores (light-reflecting cells) responded to the light. The response changed depending on the wavelength of light, and the cells were most sensitive to blue light.
Researchers then looked deeper at this mechanism, and found that sensory neurons in the octopus skin synthesize one version of the opsin protein, a light-sensitive molecule found in eyes.
As phenomenal as this ability is, the octopus is not the only creature found to be capable of seeing with its skin. In fact, even humans have been proven to have this ability, albeit in a more limited way. Research has shown that human skin cells can actually "see" ultraviolet light, and that this is the mechanism that triggers tanning.
Now if only we could also taste with our skin, generate light with it, and instantly camouflage ourselves by altering our shape and color, as the octopus can.
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