Sharks' Secret Weapon

Sharks have a secret weapon in their snouts that helps them hunt prey. It's an organ that can sense faint electrical signals given off by other, delicious creatures. Now, engineers in Indiana have made a new material for electronics that mimics the shark's sensor. It even works in salt water, which is usually a harsh environment for electronics. (Drop your smartphone in the ocean, for instance, and that’s the end of the phone.)

The new device may be useful in ways from studying marine life to building new tools for submarines. It’s made from a substance called samarium nickelate, or SNO. And it can detect some of the weakest electric fields found in the sea.

Many marine animals, from tiny clams to big fish, produce electric signals. Sharks and other ocean predators, including skates and rays, sense those electric fields. They do it using organs known as ampullae (AM-puh-lay) of Lorenzini. Scientists call such tissues electroreceptors because they detect electric fields.

The ampullae look like a line of small holes, or pores, near the mouth on a shark's snout. Those pores lead to short channels filled with a jelly-like substance. At the other end of the channels, behind the jelly, are special sensing cells.

When a fish swims nearby that gives off an electric field, those cells send signals to the shark's brain: “Dinner!”

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