Researchers from the Polytechnic Institute of New York University designed a robotic fish that closely mimics the tail movements of a real live fish. It doesn't look like much--it doesn't even have a face--but it beats its tail and moves in a fashion similar to the real thing. The team then dropped their fish-bot into a water tunnel full of golden shiners to see what they'd think of it. When floating still, the school of fish couldn't care less about the impostor's presence. When switched on, however, the shiners responded instinctively to its motion. As the fastest-moving fish in the school, the robot was immediately assumed to be the leader, and the school followed it without hesitation.
This seems to be the first time that biomimetic robots have been used to control animal behavior. The team hopes to develop their prototype into a device that would help steer schools of fish away from environmental disasters, like oil or chemical spills. If fish are so easily fooled, they could easily be persuaded not to hang out in areas that might kill them with toxins. The same principle could be applied to help other animals that behave collectively, such as birds. Although I get the idea that birds are a little more wary of eyeless, faceless leaders than your average fish.