According to a new study from the University of California at Santa Barbara and published in the Journal of Experimental Biology, octopuses can see light with their skin.
It is already common knowledge that the family of cephalopods, including squid, octopuses and cuttlefish are the masters of disguise in the marine environment, changing the pattern, texture and color of their skin to safely roam their territories, hopefully without falling prey to larger predators.
An awe-striking evolutionary advancement which makes cephalopods the envy of military and intelligence agencies around the world looking to develop cloaking devices.
Cephalopods are enabled to create all of this easily thanks to the dense fabric of specialized cells in their skin. And although the skin doesn’t ‚see’ as keen as the eye, it seems that both are triggered by the light-sensitive opsins which are usually found in the eye.
According to the study, in the case of octopuses, this isn’t so much seeing as it is a sensory perception which doesn’t even require input from the central nervous system.
To come to this conclusion, Dr. Desmond Ramirez and Dr. Todd Oakley recovered patches of skin from 11 bimac octopi, both hatchling and adult, pinned them to Petri dishes and set diodes to shine different light of a variety of wavelengths on the samples.
What they noticed was that the pigmented chromatophores that cephalopods usually present underneath the skin, fenced by muscles as well as nerve endings, reacted differently to each wavelength. For bright white light, the chromatophores expanded rapidly and kept their status while pulsating rhythmically.
Red light and blue light caused a rhythmic contraction of the muscles, but not an expansion of chromatophores. In the absence of light, the skin samples returned to their initial hue. Dr. Ramirez commented:
“It can sense an increase or change in light. Its skin is not detecting contrast and edge, but rather brightness.”
Contrasting with the cuttlefish which produce opsins in their skin, octopuses produce the protein in the nerve endings underneath the skin. This enables them to detect the light wavelengths and triggers the chromatophores to camouflage these amazing marine creatures.
The family of cephalopods usually presents as much as 96,000 chromatophores per square inch of skin. That is an entire network of camouflage design.
Both Dr. Ramirez and Dr. Oakley are satisfied with the results of their study. It helps advance knowledge on cephalopods, some of the marine world’s most intelligent and puzzling creatures, and octopuses in particular.
Image Source: MarineBio