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How A Fish’s Armor Might Help The Military

— This is the type of story you might expect to see as a low-budget monster movie - a 300-pound fish versus a school of starving piranhas.

In this case, the big fish - an arapaima - always wins.

Arapaimas thrive in piranha-infested waters in the Amazon.

This fact inspired Marc Meyers, a professor at the Jacobs School of Engineering at UC San Diego, to research the arapaima’s armor-like scales in hopes of discovering a useful application, like better body armor for soldiers.

“The materials that nature has at its disposal are not very strong, but nature combines them in a very ingenious way to produce strong components and strong designs,” said Meyers.

Meyers and his research colleagues used mechanical and aerospace engineering techniques to test every aspect of arapaima scales.

First, they attempted to drill a piranha tooth through each scale. No luck there.

Then, the researchers microscopically deconstructed the scales, which revealed their secrets to structural security.

Meyers found that overlapping fish scales repel penetration because of an outer hard coating that wraps around rows of collagen fibers, stacked in alternating directions, like a neatly stacked pile of plywood.

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

It’s a combination the research engineers would like to copy for things like a better body armor, fuel cells, insulation, or aerospace designs.

It’s also a discovery that lets one believe the incredible survival stories of knights in shinning armor aren’t so fishy after all.


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