How octopuses squeeze through holes that seem impossibly tiny

Octopuses are famous for slipping through seemingly impossible gaps. Scientists have now mapped how they do it, finding that these marine invertebrates organize their eight arms and soft bodies into a sequence that changes when the opening gets tighter — a strategy that could offer lessons for robots designed to enter confined spaces. Unlike humans and other animals with rigid skeletons, octopuses have extremely flexible bodies built around what scientists call a muscular hydrostat, a system of muscles that provides both support and movement without bones. Their eight dexterous arms can bend and elongate, while their central mantle can change shape. The animal's circulatory system is also suited to contortions: major blood vessels have muscular pumping systems that help keep blood moving locally even when part of the body is constricted.