Why an Octopus Arm Is Essentially a Brain That Can Taste and Smell
In short: An octopus does not just use its eight arms to grab or move; it uses them to sense the world. Each of the hundreds of suckers lining those arms functions like a tongue or a nose, allowing the animal to taste and smell its environment through touch alone.
The octopus is a soft-bodied creature that lacks a skeleton, making it vulnerable as a meal for predators. To survive, it has evolved a unique anatomy that relies on a muscular hydrostat—a system where muscles are arranged in various directions to provide resistance, much like the bones in a vertebrate. This same arrangement is found in elephant trunks and human tongues, allowing for complex, flexible movement without any rigid support.
Because the octopus body is so soft, it requires a sophisticated nervous system to manage its movements. An octopus possesses about 500 million neurons, a count comparable to the 600 million found in dogs. Crucially, these neurons are not centralized; two-thirds of them reside within the arms themselves. According to neurobiologist Binyamin Hochner, this distribution is a matter of efficiency, effectively turning each arm into a brain of its own.
This decentralized control allows the arms to operate with a degree of independence. While the central brain, located between the eyes, provides high-level commands regarding direction and speed, the specific mechanics of reaching are handled locally by the arms. This autonomy is essential for navigating the world, as the suckers—which can number up to 240 per arm in species like the Giant Pacific octopus—constantly process sensory data. By offloading these tasks, the octopus can navigate its environment with remarkable speed and precision, using its limbs to taste and smell as it explores.
Opens the Intellect+ feed with this card first. Swipe up for the next one.
Sources
- Summary by Intellect · source: If Your Hands Could Smell, You’d Be an Octopus | Deep Look
To cite this card, link to https://intellectplus.co.uk/app/nature-if-your-hands-could-smell-you-d-be-an-octopus-deep-look.
How we source, check and correct cards: Editorial standards.
General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.
Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?
Related
More in Nature · Latest · A–Z · All topics
