Everyone knows sharks are fierce predators.  How exactly they hunt so well is in part due to their extra sixth sense: electroreception!


Exactly how sensitive are the ampullae of Lorenzini?

By measuring brain activity, scientists can test how large electrical changes have to be for a shark to notice.  They found that sharks can sense change as small as 15 billionths of a volt.  This is like placing a AA battery in the ocean with the two poles 900 miles apart — the hammerhead shark could still tell when the batter was switch off and on.

Even with the most modern equipment, engineers have trouble measuring electrical changes that small!

Aren’t you glad you don’t qualify as hammerhead shark prey?



Scientific American: The Shark’s Electric Sense

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