An octopus has arms with powerful suckers, but those suckers won't grab onto the octopus itself.
Researchers have finally gained insight into how these animals keep themselves from getting tangled up, a Cell Press news release reported. The octopus's brain can be unaware of the process, but a secreted chemical temporarily works to disable the suckers.
"We were surprised that nobody before us had noticed this very robust and easy-to-detect phenomena," researcher Guy Levy said in the news release. "We were entirely surprised by the brilliant and simple solution of the octopus to this potentially very complicated problem."
Octopuses are not aware of their arms in the same way other animals are.
"Our motor control system is based on a rather fixed representation of the motor and sensory systems in the brain in a formant of maps that have body part coordinates," researcher Binyamin Hochner said in the news release.
Humans have rigid skeletons that movements much more limited.
"It is hard to envisage similar mechanisms to function in the octopus brain because its very long and flexible arms have an infinite number of degrees of freedom," Hochner said.. "Therefore, using such maps would have been tremendously difficult for the octopus, and maybe even impossible."
To make their findings the researchers looked at amputated octopus arms; these arms can stay active for up to an hour after amputation.
The team found the octopus arms never grabbed onto octopus skin, but they would grab a skinned amputated arm. The octopus was also unable to grab onto a Petri dish covered in octopus skin.
"The results so far show, and for the first time, that the skin of the octopus prevents octopus arms from attaching to each other or to themselves in a reflexive manner," the researchers wrote, the news release reported. . "The drastic reduction in the response to the skin crude extract suggests that a specific chemical signal in the skin mediates the inhibition of sucker grabbing."
The researchers have not identified the chemical that keeps the octopus from grabbing onto itself. The phenomenon could even help inspire robot design.
"Soft robots have advantages [in] that they can reshape their body," Nesher said "This is especially advantageous in unfamiliar environments with many obstacles that can be bypassed only by flexible manipulators, such as the internal human body environment."
