electroreceptors

Electroreceptors are sensory receptors that detect electric fields and transduce electrical stimuli into neural signals. They occur in a variety of aquatic animals and, in a few terrestrial mammals, in specialized skin or bill structures. Electroreception can aid in locating prey, navigating environments, and perceiving objects in the surrounding water.

In fishes, electroreception is commonly classified into passive and active forms. Passive electroreception is mediated by ampullary organs that detect weak ambient electric fields generated by living organisms. These organs are found in many cartilaginous fishes (such as sharks and rays) and in a broad range of bony fishes. Ampullary receptors respond to low-frequency or near-DC fields through canal systems that lead to embedded receptor cells, enabling the animal to sense the electrical signatures of prey or obstacles.

Active electroreception, or electrolocation, relies on tuberous electroreceptors that are sensitive to the animal’s own electric field, which is produced by specialized electric organs. In certain electric fish groups, such as gymnotiforms and mormyrids, the self-generated electric field is distorted by objects or prey, and the receptors detect these distortions to form a picture of the surroundings. This modality often provides high sensitivity and rapid spatial information, supporting navigation and hunting in murky water.

Terrestrial and semi-aquatic mammals also exhibit electroreception. The most notable example is the platypus, and to a lesser extent echidnas, which possess electroreceptors in their bill. In the platypus, these receptors contribute to prey detection in dark or turbid water by sensing the electrical activity of prey muscles.

Evolutionarily, electroreception has arisen independently multiple times and shows substantial variation in anatomy and processing. Its study informs understanding of sensory diversity and the neural integration of electric information.