The nine weapons and the quirks of the nervous system of the cephalopods

Nine arms, no problem

In 2021, researchers from the Marine Research Institute in Spain used an underwater camera pursue a male Octopus vulgaris, or common octopus. On its left side, three arms were intact, while the others were reduced to uneven and tarmac lengths, suddenly bitten at different points. Although the researchers were not witness to the injury itself, they observed that the right front arm – known as R1 – were unusual, dividing into two distinct members and giving the octopus a total of nine arms.

“In this individual, we believe that this condition was the result of abnormal regeneration [a genetic mutation] After a meeting with a predator, ”explains Sam Soule, one of the researchers and the first author on the article recently published in Animals.

The researchers appointed the octopus Salvador because of its branched arm wound on itself as the two reversed ends of Salvador Dali's mustache. For two years, the team studied the behavior of the cephalopod and find That he used his branched arm less when he made “more risky” movements such as exploration or seizure of food, which would force the animal to stretch their arm and expose it to an injury.

“One of the conclusions of our research is that the octopus probably retains a long -term memory of the initial injury, because it tends to use bifurcated weapons for less risky tasks compared to others,” says Jorge Hernández Urcera, a main author of the study. “This idea of ​​a sustainable memory was the subject of a famous painting by Dalí The persistence of memoryWho ultimately became the title of the document we have published on the surveillance of this particular octopus. »»

While the octopus acted more protective of its additional member, its nervous system had adapted To use the additional appendix, as the octopus was observed, after a while, recovering from its injuries, using its ninth arm to probe its environment.

“This nine weapons octopus is a perfect example of how these animals are adaptable,” adds Pelled. “Most animals would have trouble with an unusual part of the body, but not the octopus. In this case, the octopus had a branched arm (divided) and always used it effectively, like any other arm. This tells us that the nervous system did not treat it as an error – he understood how to make it work.”

Kenna Hughes-Castleberry is the scientific communicator of Jila (a research institute in joint physics between the National Institute of Standards and Technology and the University of Colorado Boulder) and an independent scientific journalist. Its main writing objectives are quantum physics, quantum technology, deep technology, social media and the diversity of people in these areas, especially women and people from minority and racial ethnic groups. Follow her Liendin or visit Son website.