The discovery that some octopuses use a pair of their tentacles to “walk” on the seafloor may spur development of soft robots. Whereas most bipedal locomotion requires the support of a rigid 
skeleton, these creatures use two arms in a rolling motion, similar to a tank tread, to propel themselves.
Scientists at the University of California, Berkeley, have studied the animals’ gait and built an artificial limb segment that could eventually become a robotic arm. A tube with a spring inside, it can be maneuvered via electrical current.
Although the prototype uses a metal frame, the researchers expect to develop a device supported only by musclelike bands, such as those of their marine model. The goal is a flexible robot that can wriggle into places where rigid relatives can’t go.