Israelis discover how octopi keep from getting tangled
Hebrew U. scientists find that creature’s arms sense a chemical produced by their skin, keeping them from latching on
Lazar Berman is The Times of Israel's diplomatic reporter
Israeli scientists have made a series of important discoveries — quasicrystals, quarks, black-holes entropy — that change experts’ understanding of the world.
But a recent discovery by Israeli researchers at the Hebrew University of Jerusalem’s Octopus Research Group might be the most consequential one yet.
The four scientists — Nir Nesher, Guy Levy, Frank W. Grasso, and Binyamin Hochner — discovered how octopi, with their eight long tentacles, manage to keep them from getting tangled. This is all the more perplexing since their brains do not know where each arm is at a given time.
They published their findings Thursday in the journal Current Biology.
The team found that the suckers on the tentacles do not stick to octopus skin: They manage this by sensing a chemical produced by the skin.
To reach their conclusion, the scientists took amputated octopus arms, which can remain alive on their own for an hour. They found that the tentacles attached themselves to every type of surface except other octopus arms.
“In more than 30 trials during the preliminary observations,” they wrote, “we never saw the suckers of amputated arms attach to the arm itself or to another arm covered with skin, whether they originated from the same animal or from different animals.”
However, when the team put skinned octopus arms in reach of the amputated ones, the suckers latched onto the skinless flesh.
“We were entirely surprised by the brilliant and simple solution of the octopus to this potentially very complicated problem,” the researchers said, according to the Daily Mail.
However, octopi do eat each other, and the scientists found that live specimens do sometimes grab amputated arms. This, they wrote, suggests that “central brain control can override (veto) the inhibition of the reflexive attachment behavior.”
Live octopi also seemed able to recognize their own amputated arms versus those from another specimen.
They also found that many octopus movements are highly redundant, almost reflexive, simplifying the control of the eight arms.
In the article summary, the researchers suggested that their findings on octopus motor control and self-awareness could have important implications for the development of autonomous robots.
