How a fish can “see” a meal’s electricity
A moving animal is not electrically silent. As its muscles contract, they create tiny voltage differences in the surrounding water. The fish can detect these weak signals with electroreception—the ability to sense electrical fields rather than light or sound.
In many electroreceptive fish, including sharks and rays, the sensors are called ampullae of Lorenzini. They sit in the skin around the head, with small pores opening onto the surface. Each pore connects to a fluid-filled canal leading to sensitive cells. When an outside electrical field reaches those cells, it changes their activity, giving the fish information about the signal’s direction and strength.
A close-range sense for murky water
Electricity does not provide a sharp picture of prey from far away. Its field weakens with distance, so electroreception is most useful when a target is nearby. But it can work when visibility is poor—over dark sand, in cloudy water, or at night—when a visual search would be difficult.
The fish can combine this hidden cue with other senses, narrowing down where to strike. A slight movement in the sediment may be hard to see; the muscle activity of the animal beneath it can still betray its location. The result is a practical advantage at the moment ordinary sight has the least to offer.
