Why every arm of an octopus moves with a mind of its own
There are many remarkable things about octopuses—they’re famously intelligent, they have three hearts, their eyeballs work like prisms, they can change color at will, and they can “see” light with their skin. One of the most striking things about these creatures, however, is the fact that each of their eight arms almost seems to have a mind of its own, allowing an octopus to multitask in a manner that humans can only dream about. At the heart of each arm is a structure known as the axial nervous cord (ANC), and a new study published January 15 in Nature Communications examines how the structure of this cord is fundamental to allowing the arms to act as they do. Cassady Olson, first author on the paper, explains to Popular Science that understanding the ANC is crucial to understanding how an octopus’s arms work: “You can think of the ANC as equivalent to a spinal cord running down the center of every single arm.” Olson explains that “there are many gross similarities [between the ANC and vertebrates’ …