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The brainbox of the deep

Octopuses are, like us, highly intelligent beings, say Emily Knight and Becky Ripley on BBC Radio 4’s NatureBang. But our brains have evolved very differently – hardly a surprise, given that our last common ancestor was a “flatworm that trawled the sea floor around 750 million years ago”. An octopus has a central brain wrapped around its throat, but its eight arms are also packed with neurons, allowing them to act independently. A severed arm can think and theoretically hunt by itself – so before the arm dies, an octopus can exist “in two places at once”.

In fact, it’s possible that octopuses have a “sense of multiple selves”, says Sy Montgomery, author of The Soul of an Octopus. They appear to have “some shy arms and some bold arms”, just as humans have different sides to their characters. What’s more, the cephalopods experience a range of emotions. They even have an equivalent to our love hormone oxytocin. It just shows that emotion, memory and consciousness are not uniquely human characteristics – “we do not own them”.

Listen to the full episode here.