Electroreception: a shocking sense

ELECTRICITY IS THE RESULT OF interactions between objects with electric charge - and batteries aren't the only things that can be charged.

- EVOLUTIONARY BIOLOGIST JV CHAMARY

Like the top and bottom of a battery, the inside of a living thing can have a negative charge while the outside is positive, or vice-versa, making it electric.

What is electroreception?

It's the ability to sense an electric field, the physical forces produced by attraction and repulsion (electromagnetism) between charged objects, which spreads through a surrounding medium like ripples in a pond. In water, the charge across an animal's surface interacts with dissolved molecules in the medium: opposite charges attract, like-charges repel.

Electroreception can be passive or active. For the passive sense, an animal detects electric fields created by other individuals (such as nearby predators, prey or mates) due to the charged surface of their bodies or muscle movements, which are controlled by electrical impulses and so affect the surrounding field.

How are electric fields detected?