Scientists: Why Don't Octopuses Tie Themselves in Knots?

Scientists behind a recent study aimed to answer the question: why don't octopuses, with their sticky suction cups, tie themselves in knots?

The answer lies in their chemical makeup. By deactivating its suckers, a chemical in octopus skin stop's the animal's limbs from tangling up in each other, according to a new study published today in the journal Current Biology.

The question arose when the team was faced with a freshly dismembered octopus arm that eagerly clung to everything it touched, except itself, The Guardian wrote.

Octopuses can camouflage themselves, morph into the shape of other beasts, and even regrow lopped off limbs, and yet even they cannot keep track of all eight of their tentacles.

"We thought about it and we said, 'How is it possible that the arms don't grab each other?'" Guy Levy of the Hebrew University of Jerusalem in Israel questioned, according to NPR.

Of the octopus's 500 million nerve cells, more than half are in their arms, but they still cannot control them effectively.

Researchers studied severed octopus arms, which remain active for more than an hour after amputation, and found that the suckers didn't latch on to its own skin or the skin of any other arm, whether it was from the same octopus or other octopuses. But when they removed the skin from the arms, the suckers would stick to it.

"We kind of said to ourselves, aha, this is it! This is the answer, this how it doesn't get tangled," Levy said. "We didn't know the details yet, but we saw that there is something."

Collaborator Binyamin Hochner and Levy's team have not yet identified the active agent responsible for the animal's self-avoidance behavior. The findings suggest that octopuses have a chemical in their skin that stops their suckers from sticking.

"It's a brilliant solution to what could be a really complex problem," Hochner told The Guardian.