When an electric knifefish encounters a rival, both boost their electric field in an effort to jam the other's signal. Previous research has shown that distorting the fish's electric field screwes up its "guidance systems." The scientists who conducted the experiments, Sara Tallarovic of the University of the Incarnate Word and Harold Zakon of the University of Texas, recorded knightfish fish doing battle, including the zaps converted into audible sound. The intense videos are available as part of a Science News article about the research. From the article:
A fish of this species occasionally raises its frequency but never lowers it, Tallarovic says. She suspected signal jamming when she noticed upward frequency shifts as one fish attacked another. "Everybody just told me, 'No, it's got to be an artifact,'" she says.So, she and Zakon monitored fishes' electric fields in several scenarios, the team reports in an upcoming Animal Behaviour. When researchers put two fish in an unfamiliar tank or used a field-emitting dummy to mimic an intruder in a fish's home tank, both males and females tended to raise their electric-field frequencies as they attacked. The changes' timing and context convinced the researchers that the attacking fish was jamming the other's signals.
