Section through an octopus shows the mouth passing through the brain

Octopuses and other cephalopods are well-known for their exceptional intelligence and complex brains, which appear to outstrip all other invertebrates’. But, they work within one strange constraint – like all other molluscs (snails, slugs, oysters and more), the nerve ring at the centre of their nervous system encircles the oesophagus. In cephalopods, this nerve ring…