Quick answer
Octopuses are widely considered the most intelligent invertebrates on Earth. They use tools, solve puzzles, open jars, navigate mazes, and recognise individual humans. Remarkably, two-thirds of their neurons are in their eight arms, not the central brain — giving each arm a degree of independent 'thinking'.
Octopus intelligence at a glance
| Total neurons | Around 500 million (similar order to a dog) |
| Neuron distribution | ~2/3 in the arms, ~1/3 in the central brain |
| Tool use | Yes — e.g. carrying coconut shells for shelter |
| Problem-solving | Opens jars, solves mazes and puzzles |
| Memory | Both short- and long-term |
| Recognises humans | Can distinguish individual people |
Just how smart are octopuses?
Octopuses are the standout intellects of the invertebrate world. With on the order of 500 million neurons — a count in the same broad range as a dog's — they show abilities once thought to belong only to vertebrates: they solve puzzles, learn by trial and error, remember solutions, and even appear to play with objects when not hungry. Aquarium keepers regularly report octopuses recognising and behaving differently toward individual staff.
What makes this more astonishing is that octopuses evolved their intelligence completely independently of ours. Our last common ancestor was a simple worm-like creature hundreds of millions of years ago, so the octopus represents a separate experiment in how to build a mind — which is why studying them is so valuable to science.
Tool use and problem-solving
Octopuses are among the very few invertebrates known to use tools. Some species collect discarded coconut shells or seashells and carry them across the seabed to assemble into portable shelters — planning ahead for a future need, which is a sophisticated cognitive feat. In captivity they famously open screw-top jars to reach food inside, sometimes from the outside and sometimes from within.
They are also relentless problem-solvers and escape artists. Octopuses squeeze through gaps barely larger than their beak, dismantle tank fittings, and have been documented climbing out of aquariums and across floors to raid neighbouring tanks before returning. This combination of curiosity, dexterity, and persistence is the hallmark of their intelligence.
A mind spread through the arms
The strangest feature of octopus intelligence is where it lives. Roughly two-thirds of an octopus's neurons are located not in the central brain but distributed through its eight arms. Each arm contains its own dense nerve network and can taste, touch, and react with a measure of independence — effectively doing its own local processing while the central brain handles the bigger picture.
This decentralised design is why octopuses are sometimes described as having 'nine brains'. It allows an octopus to explore a reef with all eight arms at once, each one investigating crevices semi-autonomously. It is a radically different way of organising a mind from the centralised brains of mammals, and a major reason scientists find these animals so fascinating.
Octopus intelligence: FAQs
Are octopuses really intelligent?
Yes. Octopuses are considered the most intelligent invertebrates, capable of using tools, solving puzzles, opening jars, navigating mazes, and recognising individual people. They have roughly 500 million neurons, a count in the same range as a dog's.
How many brains does an octopus have?
An octopus has one central brain plus a major nerve cluster in each of its eight arms, so it is often said to have nine 'brains'. About two-thirds of its neurons are in the arms.
Do octopuses use tools?
Yes. Some octopuses collect coconut shells or seashells and carry them to build portable shelters, which is one of the few clear examples of tool use in an invertebrate.
Can octopuses recognise people?
Aquarium observations suggest octopuses can distinguish individual humans and may behave differently toward different people, for example squirting water at staff they appear to dislike.
How do octopuses escape their tanks?
Octopuses are boneless and can squeeze through any gap larger than their beak. Combined with their problem-solving ability, this lets them open lids, climb out of tanks, and even raid neighbouring tanks before returning.
Why are octopuses so smart compared to other invertebrates?
Octopuses evolved a large, complex nervous system independently of vertebrates, likely driven by an active predatory lifestyle and the need to control eight flexible arms and rapid camouflage. This makes them a unique, separately evolved example of intelligence.