An octopus has 9 brains — one central and one in each arm
Some trivia is so bizarre it forces you to rethink your entire understanding of the world. Check out the fact below, see how others reacted, and scroll down to dive into the verified science and history behind it.
An octopus has a central brain that coordinates overall behaviour, but each of its eight arms also contains its own cluster of neurons — essentially a local brain — that can operate semi-independently. About two-thirds of an octopus's neurons are in its arms, not its central brain. An arm that has been severed from the body can continue to respond to stimuli and attempt to bring food to where the mouth used to be for up to an hour. The arms effectively 'think' locally, reducing the processing load on the central brain.
We conceptualise brains as singular centralised control centres. Discovering that an animal distributes its cognition across nine semi-independent processing units — with arms that can act intelligently without consulting the head — makes the concept of 'a brain' feel much less settled.
The Science Behind It
An octopus has a central brain that coordinates overall behaviour, but each of its eight arms also contains its own cluster of neurons — essentially a local brain — that can operate semi-independently. About two-thirds of an octopus's neurons are in its arms, not its central brain. An arm that has been severed from the body can continue to respond to stimuli and attempt to bring food to where the mouth used to be for up to an hour. The arms effectively 'think' locally, reducing the processing load on the central brain.
Why Your Brain Finds This Hard to Believe
Sources & Verification
OddlyHuman Editors
VerifiedWritten and fact-checked by the OddlyHuman Behavioral Science Team. We verify all psychological, sociological, and historical claims against peer-reviewed journals, primary sources, and established encyclopedias to bring you accurate insights.
Read our Editorial Guidelines →“An octopus has 9 brains — one central and one in each arm. Two-thirds of its neurons are in its arms. A severed arm will still try to bring food to where the mouth used to be. 🐙 #OddlyHuman”