Now some are taking a step forward and actually building these materials. At the University of California, San Diego, materials science professor Marc Myers has been studying the scales on the massive freshwater arapaima, which use two layers of scales to repel bites from the predatory piranha. Piranha normally don't attack the arapaima, which can grow to nearly 8 feet long and weigh more than 500 pounds, however when food supplies are low and water levels drop in the Amazon basin, everything in the water is considered a meal, Myers said.
_Myers likes to go fishing in the Amazon, and once hooked a 100-pound arapaima. At his lab in San Diego, Myers used a special device to press a piranha tooth into the arapaima scales to measure the force it took to penetrate them. But the piranha tooth failed to penetrate into two layers and broke when it was pulled out. "What arapaima have are fairly thick triangular ridges that other fish don't have," Myers said. "It can bend at same time, like a ceramic that would be flexible." The outer scales are mineralized bio-material, while the inner ones are made of collagen fibers that form a flexible laminate, almost like a woven cloth.