Underwater robots face many challenges before they can truly master the deep, such as stability in choppy currents. A new paper published in the journal npj Robotics provides a comprehensive update of where the technology stands today, including significant progress inspired by the movement of rays.Underwater robots face many challenges before they can truly master the deep, such as stability in choppy currents. A new paper published in the journal npj Robotics provides a comprehensive update of where the technology stands today, including significant progress inspired by the movement of rays.[#item_full_content]