The idea is to catch subs and mines, not kids swimming off of the Florida coast. But the methods could wind up being largely the same. The Navy has tapped three firms to build prototype gadgets that duplicate what sharks do naturally: find prey from the electric fields they emit.

A shark doesn't use its eyes to find its next meal. It relies on jelly-filled canals inside its head to pick up on the tiny electrical charges that potential morsel makes when it flexes its muscles, or swims counter to the earth's magnetic fields.

It's a real-live sixth sense. And it's something the Navy would like to exploit as its sailors look for subs and mines in the crowded coastal waters.

San Diego's RD Instruments is one of three companies that have received Navy small business grants to try and pull off the trick.

The sharks themselves will be our initial guides into what is possible. We will quantify the shark's ability to detect nonelectrogenic objects in an applied electric field, and determine the extent to which we can emulate it with custom-built electrodes. Once feasibility is determined, we will propose a prototype sensor capable of deployment on a variety of COTS [commercial, off-the-shelf] platforms.

THERE'S MORE: Meanwhile, three other small businesses have won Air Force contracts to make laser-proof contact lenses for pilots. Laser targeting and defense systems are growing more common in the skies above a battlefield. And that means more chances for flyboys to get zapped in the eye.

Houston's Nanospectra Biosciences thinks it can provide protection by embedding in contacts "a new class of optically tunable nanoparticles [that can] extinguish target wavelengths of light."

Reveo Inc., on the other hand, is banking on "a thin, flexible, polymeric reflecting film on or within the lens... The film is engineered to reflect completely incident light in the far red and near infrared (670 nm - 1,200 nm) regions, while remaining highly transparent (> 90%) elsewhere in the visible range."

AND MORE: Defense Industry Daily breaks down how these Pentagon "Small Business Innovation Research" contracts work.

(photo credit: Callaghan Fritz-Cope/Pelagic Shark Research Foundation)