National Geographic : 2010 Feb
PHOTO: TIM LAMAN TECHNOLOGY Robo-fish Imagine a school of fish weaving through a network of pipelines at the bottom of a bay. Only instead of live fish foraging for food, these are robots patrolling for damage and pollutant leaks. Robo-fish can fit in places divers and submarines can't. The first robotic fish, built in the 1990s, were around four feet long, had thousands of parts, and cost thousands of dollars. The newest, designed by MIT researchers Kamal Youcef-Toumi and Pablo Valdivia y Alvarado, are five to eighteen inches long, have about ten parts, and cost just hundreds of dollars. These sleek robots are made of a seamless, synthetic compound engineered to be flexible in places where fish bend a lot---the tail---and rigid where they don't---the midsection. A single motor sends a wave down the interior, and the motion of the material mimics the swimming motion of a real fish. Although the latest robotic fish are pretty close to making a splash, they are not yet swimming in lakes and oceans. It'll be a few more years before you can tell the story about the robo-fish that got away. ---Juli Berwald Robotic fish, strung up in an MIT lab, have lasted for four years in tests conducted in tap water.