An octopus has three hearts, blue blood, and two-thirds of its neurons in its arms. It opens jars, solves mazes, and changes color while colorblind — a mind that evolved utterly unlike our own.
Mark Rober built an elaborate underwater obstacle course for his pet octopus, Sashimi — and watched her reason her way through it.
NOVA explains how an octopus's intelligence is spread through its arms — each one tasting, touching, and partly deciding on its own.
A lab octopus works out how to navigate a maze to reach a meal — a classic demonstration of cephalopod problem-solving.
Biologist Roger Hanlon shows an octopus vanish into a reef in under a second — and asks how a colorblind animal matches color so perfectly.
The biology behind the strangeness: copper-based blood, a doughnut-shaped brain, skin that senses light, and the ability to squeeze through any gap bigger than its beak.
Tool use, play, individual personalities, and escape artistry — the evidence that octopuses and their cousins are the most intelligent invertebrates alive.
Philosopher Peter Godfrey-Smith argues the octopus is an independent experiment in evolving a mind — the nearest thing on Earth to meeting an intelligent alien.