Octopus skin can detect light and respond to it — no eyes or brain required.

Tests of fresh skin samples from California two-spot octopuses (Octopus bimaculoides) show this ability clearly for the first time in any cephalopod, says Todd Oakley of the University of California, Santa Barbara. White or blue light prompts the pale skin’s tiny quick-change color organs, or chromatophores, to expand, creating waves of yellows and browns.