On a Limb: How an Octopus Regrows Its Arms | Mental Floss

MBL cephalopod scientist and Hibbitt Fellow Carrie Albertin discusses regeneration in octopuses in this Mental Floss story.

In the 2020 Oscar-nominated documentary My Octopus Teacher, filmmaker Craig Foster strikes up a fascinating friendship with a wild octopus in a South Africa kelp forest. In one scene—mild spoiler here—the mollusk suffers what appears to be a grievous injury when a shark rips off one of its arms.

Slowly, seemingly miraculously, the cephalopod’s appendage begins to grow back. This is especially impressive considering that octopuses host two-thirds of their neurons in their arms, thanks to nerve cords in each that act much like a spinal cord does in humans. So what happens when they lose not only a limb, but also part of their nervous system?

Photo: California two-spot octopus. Credit: Michael LaBarbera