A \"soft\" robot inspired by squid and starfish can crawl, undulate, and squeeze under obstacles.Built by a team at Harvard University, this robot has several advantages over those with treads, wheels and rigid parts - which have a limited repertoire of movements and may have trouble navigating difficult terrain.The sea creature-inspired creation was manufactured with soft materials and its motion is driven by compressed air.Details appear in the journal PNAS.Professor George Whitesides, Robert Shepherd and their colleagues from Harvard University in Cambridge, US, said the work was inspired by animals such as squid and starfish that lack hard skeletons.The pneumatically-driven robot is built using flexible materials known as \"elastomers\".Contained within the elastomer layer is a series of chambers that inflate like balloons to enable motion.The robot can adopt different patterns of movement (gaits) during locomotion and its limbs are capable of fluid motions, the Harvard engineers explain.They put their creation through its paces on an obstacle course which, they say, would hinder some rigid, metallic robots.The flexible robot was made to squeeze underneath a glass plate elevated 2cm above the ground in less than a minute by executing a combination of co-ordinated movements.Soft robots are more resistant than more rigid designs to damage from some common hazards in a real-world setting, such as falling on rocks, or receiving bumps and scrapes from other hard objects.But the authors concede that the vulnerable elastomer \"skins\" of soft robots make them more susceptible to punctures from objects such as broken glass or thorns.