Each Arm of an Octopus Has a Mind of Its Own

The tentacles of an octopus are impressive in their fluidity, but there's even more going on in that appendage that's just under the skin. Olga Visavi/Shutterstock

Have you ever wondered how an octopus manages to choreograph eight arms all moving around at once? As it reaches out to snag a meal, how does it know when it latches on to something tasty?

The secret lies in the hundreds of suckers running down each arm — which act sort of like a nose and a tongue — and to the millions of neurons in each arm.

Arm Communication

KQED Science explains the incredible ability:

It has about 500 million neurons (dogs have around 600 million), the cells that allow it to process and communicate information. And these neurons are distributed to make the most of its eight arms. An octopus’ central brain – located between its eyes – doesn’t control its every move. Instead, two thirds of the animal’s neurons are in its arms.
“It’s more efficient to put the nervous cells in the arm,” said neurobiologist Binyamin Hochner, of the Hebrew University of Jerusalem. “The arm is a brain of its own.”
This enables octopus arms to operate somewhat independently from the animal’s central brain. The central brain tells the arms in what direction and how fast to move, but the instructions on how to reach are embedded in each arm. Octopus arms can also work autonomously when they’re searching, like when they’re looking for food under a rock.

Curious to learn more? Check out this video that shows off just how capable these cephalopods are!

More Adaptations

The use of these eight arms and hundreds of suckers to think, act, smell and taste is only one incredible adaptation of the octopus. Recent research confirms that it even uses its skin to "see" because the skin has the same light-sensitive proteins found in its eyes, and this allows the skin to detect brightness.