The octopus is one of the ocean’s most mesmerizing inhabitants, a creature of undeniable mystique that seems to watch us from across an evolutionary chasm. Yet behind this familiar image lies a biological truth so strange it deconstructs our most fundamental ideas about what it means to have a brain, to be intelligent, and even to be a unified “self.” It is an intelligence forged in pressures alien to our own, a consciousness so thoroughly embodied that it blurs the very line between mind and flesh.
Forget everything you think you know about intelligent life. The octopus wrote its own rulebook. To understand it is to embark on a journey that dismantles our vertebrate-centric definition of a mind, exploring four truths that reveal an intelligence profoundly different from our own.
An Octopus Doesn’t Have One Brain—It Has Nine
The first step in understanding the octopus is to abandon the idea of a single, central command center. An octopus has roughly 500 million neurons, but only a fraction of them reside in its central brain. A staggering 60%, or 300 million neurons, are distributed throughout its eight arms, with the remainder housed in its large optic lobes.
Total neurons in an octopus, distributed across nine brains
Of octopus neurons located in the arms, enabling distributed intelligence
Neurons in octopus arms, each capable of semi-independent action
This is not just a matter of wiring; it’s a radical solution to an immense computational problem. The central brain of an octopus lacks a somatotopic map—a detailed, point-for-point representation of the body. For a creature with a boneless, infinitely flexible body, centrally processing and controlling every possible movement would be computationally exorbitant, if not impossible. Evolution’s solution was to outsource control. Each arm contains an axial nerve cord, a sophisticated bundle of nerves that acts as a local brain. These arm-brains can process sensory information, make decisions, and initiate complex movements with a high degree of autonomy.
This distributed network allows for an even more mind-bending capability: arm-to-arm communication that completely bypasses the central brain.
“The octopus’ arms have a neural ring that bypasses the brain, and so the arms can send information to each other without the brain being aware of it.”
This neural architecture upends our model of embodiment. The central brain acts as an executive, issuing general commands—“move toward that crevice”—while the eight arms coordinate amongst themselves to handle the intricate details, each one sensing, tasting, and acting as a semi-independent agent.
Intelligence Evolved on Earth Twice
Having seen how this mind is built, we must ask where it came from. When we think of intelligent animals—primates, dolphins, crows—we are looking at our cognitive cousins. We are all vertebrates who share a relatively recent common ancestor, meaning our intelligence stems from the same evolutionary playbook.
The octopus is the stunning exception. The last common ancestor we share with an octopus was a simple, flatworm-like creature that lived approximately 600 million years ago, possessing only a rudimentary nervous system. This means that complex, problem-solving intelligence evolved completely independently on two separate branches of the tree of life: once in vertebrates, and once in cephalopods. The octopus is a breathtaking example of convergent evolution.
Last common ancestor with octopus, showing intelligence evolved twice on Earth
“It’s an alternative model for intelligence. It gives us an understanding as to the diversity of cognition in the world, and perhaps the Universe.”
This separate origin makes the octopus a precious biological artifact. Studying its mind is not just observing a clever mollusk; it is the closest we may come to studying an alien intelligence, one that offers a profound glimpse into another way for a mind to be.
They Are Colorblind Masters of Camouflage Who ‘See’ With Their Skin
If the octopus mind evolved on a separate track, then its sensory experience of the world must also be alien to our own. Nowhere is this clearer than in its legendary ability to camouflage. Using pigment sacs (chromatophores), reflective cells (erytophores), and skin-texturing muscles (papillae), it can vanish into its surroundings in as little as 200 milliseconds.
Time for octopus to change camouflage—nearly instantaneous
This mastery conceals a paradox: scientists are confident octopuses are colorblind. How can an animal match colors it cannot see? The answer reveals a sensory world where the lines between body, eye, and brain dissolve. Octopuses perceive light directly with their skin. Their skin contains the same light-sensitive proteins, or photoreceptors, found in their eyes, allowing the skin itself to sense and react to light. This triggers the chromatophores to change color automatically, without input from the brain or eyes.
This ability is made possible by a direct neural link to the chromatophores. While an animal like a chameleon relies on a slow hormonal process that can take over 20 seconds, the octopus’s neurally controlled system is nearly instantaneous. It is a creature that sees and reacts with its entire body, a true embodiment of sensory intelligence.
Time for chameleon to change color hormonally—orders of magnitude slower
They Defy the Evolutionary ‘Rules’ of Intelligence
This journey through the octopus’s hardware, history, and senses leads to a final, profound question: why did this intelligence arise at all? In vertebrates, intelligence is almost always linked to a “slow life history”—long lifespans, extended parental care, and complex social structures that foster learning. Apes, elephants, and dolphins all fit this model.
Cephalopods tear up the evolutionary rulebook for intelligence. They possess remarkable problem-solving skills and demonstrate behaviors considered candidates for genuine foresight—such as the veined octopus carrying coconut shells as a costly, forward-planning effort to create a future shelter. Yet, they live “fast life histories.” Most octopuses live for less than two years, receive no parental care, and lead largely solitary lives.
Typical lifespan of most octopus species—fast life history despite high intelligence
The leading hypothesis for this evolutionary conundrum points to a single, transformative event around 275 million years ago: the loss of the ancestral protective shell. This left the octopus’s ancestors soft, nimble, and terrifyingly vulnerable, creating two powerful but opposing evolutionary pressures.
When cephalopods lost their ancestral shell, driving rapid intelligence evolution
- The extreme risk of predation favored a “live fast, die young” strategy, as reproducing early became the safest bet when the chances of surviving to old age were slim.
- Simultaneously, this same pressure placed an immense selective premium on intelligence. With no armor, survival now depended entirely on outsmarting predators. Brains, not brawn, became the ultimate defense.
The octopus is the astonishing result of these dueling evolutionary forces—a creature built for a short, brutal life, but armed with a brilliant mind as its primary weapon.
Conclusion: A Different Kind of Mind
The octopus is a testament to the boundless creativity of evolution. With a nervous system distributed across nine “brains,” an intelligence that arose completely separately from our own, skin that can see, and a life history that breaks all the rules, it forces us to confront the biases baked into our own definition of a mind. It demonstrates that intelligence does not require a backbone, a long life, or even a single, unified brain to be brilliant.
If a single organism can embody multiple, semi-independent ways of knowing, seeing, and acting, what does that teach us about the boundaries of a “mind” and the nature of the self?