Nine Limbs and Not a Single Concern
In a notable 2021 study, scientists from Spain’s Institute of Marine Research utilized an underwater camera to track a male common octopus, known scientifically as Octopus vulgaris. The creature showcased a peculiar body condition: while three of its arms remained intact on the left side, the right side presented stumpy remains of limbs that had been bitten off. Remarkably, the front right arm—designated as R1—was observed to be regenerating in an unusual manner, eventually splitting into two, granting the octopus a total of nine arms.
“We believe this unique condition arose from abnormal regeneration, possibly linked to a genetic mutation following a predator confrontation,” stated Sam Soule, a researcher and lead author of the study recently published in the journal Animals.
The octopus earned the name Salvador, inspired by the distinctive twisting of its bifurcated arm, reminiscent of the two ends of Salvador Dali’s moustache. Over a two-year period, the research team closely monitored its behavior, discovering that Salvador tended to minimize the use of its bifurcated limb during more perilous actions, like exploration or food retrieval, as these situations exposed it to additional risks of injury.
Despite exhibiting caution with its additional appendage, the octopus’s nervous system appeared to accommodate the extra limb; after a period of recovery, it was seen utilizing the ninth arm for environmental exploration.
“This nine-armed octopus exemplifies the remarkable adaptability of these creatures,” added Pelled. “Unlike many animals that would struggle with an atypical limb, the octopus effectively employed its bifurcated arm, integrating it as if it were any other limb. This indicates that its nervous system recognized the unusual limb not as a flaw, but as an opportunity for functionality.”
Kenna Hughes-Castleberry is the science communicator at JILA, a research institute dedicated to physics, and also works as a freelance science journalist. Her writing primarily focuses on quantum physics, technology, social media, and the representation of diverse groups in these fields. Connect with her on LinkedIn or visit her website.
