Journal of Comparative Physiology A

, Volume 192, Issue 6, pp 601–612 | Cite as

Non-visual environmental imaging and object detection through active electrolocation in weakly electric fish



Weakly electric fish orient at night by employing active electrolocation. South American and African species emit electric signals and perceive the consequences of these emissions with epidermal electroreceptors. Objects are detected by analyzing the electric images which they project onto the animal’s electroreceptive skin surface. Electric images depend on size, distance, shape, and material of objects and on the morphology of the electric organ and the fish’s body. It is proposed that the mormyrid Gnathonemus petersii possesses two electroreceptive “foveae” at its Schnauzenorgan and its nasal region, both of which resemble the visual fovea in the retina of many animals in design, function, and behavioral use. Behavioral experiments have shown that G. petersii can determine the resistive and capacitive components of an object’s complex impedance in order to identify prey items during foraging. In addition, fish can measure the distance and three-dimensional shape of objects. In order to determine object properties during active electrolocation, the fish have to determine at least four parameters of the local signal within an object’s electric image: peak amplitude, maximal slope, image width, and waveform distortions. A crucial parameter is the object distance, which is essential for unambiguous evaluation of object properties.


Electroreception Object recognition Distance 3-D shape Capacitance detection Electric fovea 



Electrosensory lateral line lobe


Electric organ


Electric organ corollary discharge


Electric organ discharge


Positive stimulus


Negative stimulus


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Neuroethologie/Sensorische Ökologie, Institut für ZoologieUniversität BonnBonnGermany

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