How does an octopus change color in a split second?

You’re swimming over a seaweed-covered rock, and then the rock opens its eyes. In under a second the octopus turns smooth and dark red and vanishes in a cloud of ink. Yet experiments suggest octopuses and their relatives probably can’t even see color. We dive into skin just a few millimeters thick: chromatophores, tiny pigment sacs with their own muscles wired straight to the brain; iridophores, mirror-like plates that make blue and green shimmer; leucophores, white cells that take on the color of the light by themselves. Then the color-blind puzzle and three scientific clues, cuttlefish patterns, papillae that turn skin into rock, the mimic octopus, messages in the skin, colors during sleep, and engineers trying to build skin like this. Every animal in this video is an illustration; chromatophore speeds were measured in squid. Never touch a blue-ringed octopus: its venom is dangerous to people. Which ocean mystery should we explain next? Tell us in the comments and subscribe for more discoveries. #Exploriny #Octopus #Science