Electrical Perception and Communication

Electric communication occurs among a few specialized fishes that have evolved electric organs for generating signals in water and electroreceptors for sensing them at close range. Behavioral analysis provides convincing evidence for communication in some of these fish – their electric discharges are displaylike: complex, patterned, and stereotyped; the discharges are given by signalers only in specific social contexts; the signals evoke characteristic responses from recipients; and when the discharges are imitated and played to recipients through electrodes, they evoke the same types of responses seen in social interactions. For these fishes, electric communication is private, fast, short-range, and temporally precise, and it can be used at night and in noisy or turbid environments, when other signaling modalities have reduced effectiveness. Electric communication is best known for two groups of freshwater teleost fishes: the Mormyriformes (c. 200 species, Osteoglossomorpha) of Africa and the Gymnotiformes (c. 160 species, Ostariophysi) of South and Central America. Fish in both groups have independently evolved tuberous electroreceptors for signal sensing and electric organs of considerable diversity for display and advertisement. There are complex electromotor pathways in the brain for the control of electric organs, and specialized electrosensory systems for signal analysis and recognition.