Washington, Feb 12 (IANS) Brazil's massive Arapaima fish might be reproduced by engineers for applications such as body armor, thanks to its intricately designed scales, a study reveals.

The inspiration for this study came from an expedition in the Amazon basin that Marc Meyers, professor at the Jacobs School of Engineering at University of California San Diego, took years ago, the journal Advanced Biomaterials reported.

The mechanical and aerospace engineering professor wondered at the Arapaima's armour-like protective scales. How could it live in piranha-infested lakes, where no other creatures could survive?

He says that engineers are pursuing biomimetics because "we are hitting a wall, so to speak" with conventional materials and syntheses, a university statement said.

Meyers and colleagues set up a lab experiment that pits piranha against Arapaima by using a machine that resembles an industrial-strength hole punch.

Piranha teeth were attached to the top "punch," which was pressed down into Arapaima scales embedded in a soft rubber surface (which mimics the soft underlying muscle on the fish) on the lower "punch."

The teeth can partially penetrate the scale, but crack before they can puncture the muscle, Meyers and colleagues demonstrated.

The Arapaima scale combines a heavily mineralized outer layer with an internal design that helps the scale resist the pirahna's razor-like bite.

The mix of materials is similar to the hard enamel of a tooth deposited over softer dentin, said Meyers, who also teaches nanoengineering in the Jacobs School of Engineering.

"You often find this in nature, where you have something hard on the outside, but it rides on something softer that gives it toughness," said Meyers.