1. When turkeys strut, their leg muscles work as shock absorbers to boost energy efficiency. That gam action inspired a prosthetic exoskeleton for humans: The lightweight contraption is outfitted with a spring and clutch that take the impact off the user's calf muscle. In experiments, a person wearing the braces while walking expended 10 percent less energy. 2. Though it has a brain, the lamprey-an eel-like beast-doesn't need it to wiggle about the deep. Neurons along the creature's spinal cord can act independently via signals called central pattern generators, or CPGs. A slithering machine inspired by the lamprey, the AmphiBot, has 10 body modules, each with its own onboard computer that mimics a CPG. The bot keeps swimming, undaunted, even after collisions. 3. Cockroaches can react in 1/50 of a second and skitter 25 body lengths per second-the equivalent of a car going 280 mph. In one test, a roach survived being squished by a mechanical press at some 900 times its body weight. The invincible bug was the model for a crushable robot made from laminated paper and weighing just 50 grams. The device can squeeze into crevices half its height-suggesting potential in search and rescue missions.