The Intelligent Shape-Shifter of the Deep

The octopus is a cephalopod of remarkable intelligence, able to solve problems, use tools and change colour and texture in an instant, and its boneless body can pour through any gap. Its many-armed strangeness made it a natural subject of art and awe: the octopus is one of the great motifs of Minoan and Aegean art of the Bronze Age, its curling arms spread across pottery and frescoes as an emblem of the living sea. Its ink, its grip and its uncanny fluidity gave it, across many coastal cultures, an association with mystery, adaptability and the hidden depths.

Octopus intelligence is now a genuinely documented field of research rather than an old sailor's impression: in a 2009 study the biologist Julian Finn recorded veined octopuses in Indonesia collecting coconut shell halves, carrying them stacked beneath their bodies across open sea floor, and assembling them into a shelter later, a sequence widely accepted as a rare case of tool use outside the vertebrates. Roughly two-thirds of an octopus's neurons are distributed through its eight arms rather than concentrated in its central brain, so each arm can taste, sense and act with a degree of independence unmatched by any other well-studied animal nervous system.