Theoretically, there are any number of ways an octopus could use its long flexible arms to move an object. But the method they actually use is surprisingly close to how animals with rigid skeletons—including humans—do it.

When hunting and grabbing dinner, the octopus uses all the flexibility the arm is capable of. But to bring captured prey to its mouth, the octopus turns the arm into a semi-rigid structure that bends to form quasi joints. Just as a human arm has joints at the shoulder, elbow, and wrist that allow our arms to bend and rotate, the octopus bends its arm to forming three segments of roughly equal length.

Understanding how the octopus controls eight flexible arms all at once could be the basis for developing the next generation of flexible robotic arms—long a goal among robotics engineers.

“Our specific aim in this project is to learn from nature how to build and control a flexible-arm robot,” said Binyamin Hochner, a biologist at Hebrew University in Jerusalem and one of the co-authors of the study. “And indeed our studies show how the octopus simplifies the complex problems associated with controlling flexible arms that have an infinitely large number of degrees of freedom. This in turn inspires the development of new strategies for the control of flexible robotic arms.”

More here.