Autonomous fish might make great leaders, but it turns out that robot flippers are a huge drain on battery life. Not a problem for Xiaobo Tan -- he and a group of Michigan State University scientists have built a robotic fish that glides through the water. Tan says the machine, dubbed Grace (Gliding Robot ACE), swims too , but the constant flipper movement can kill the battery in just a few hours. "This is why we integrated both locomotion
