Britannica Sources used in this answer

How do sharks use electrical signals to find animals hidden nearby?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Shortfin mako shark swimming in clear blue water near the surface off the West Coast of New Zealand, mouth slightly open showing teeth. — shark Shortfin mako shark (*Isurus oxyrinchus*), found throughout tropical and temperate seas worldwide.

Sharks use specialized sensory organs called ampullae of Lorenzini to detect the weak bioelectric fields produced by other organisms. These organs consist of a network of gel-filled canals located primarily on the shark's head that open to the surface through tiny pores.12

The gelatinous substance within these canals is highly conductive, allowing the shark to sense minute voltage differences—as low as 0.01 to 0.02 microvolts per centimeter—in the surrounding water. This ability, known as passive electrolocation, enables sharks to find prey, such as flatfish, even when the animals are hidden in sand, mud, or murky water where vision is limited.13

When a prey animal’s natural electric field (emanating from its gills, gut, or skin wounds) reaches the ampullae, it triggers a change in the voltage at the opening of the organ. This change alters the frequency of nerve impulses sent to the shark's central nervous system, allowing the shark to pinpoint the location of the hidden animal.132