Dear MARMAN colleagues,
On behalf of my coauthors I am pleased to share with you our newest publication on passive electroreception in bottlenose dolphins. Following our previous study published in 2022, we further investigated the bottlenose dolphin’s electroreceptive abilities and determined detection thresholds for DC and AC electric fields. Based on our findings we discuss not only the use of this electric sense during foraging but also its implications for large-scale orientation using the Earth’s magnetic field. Hüttner, T., Fersen, L. von, Miersch, L., & Dehnhardt, G. (2023). Passive electroreception in bottlenose dolphins (Tursiops truncatus): Implication for micro- and large-scale orientation. *The Journal of Experimental Biology*, *226*(22). https://doi.org/10.1242/jeb.245845 --------------------- ** Abstract ** For the two dolphin species *Sotalia guianensis* (Guiana dolphin) and *Tursiops truncatus* (bottlenose dolphin), previous research has shown that the vibrissal crypts located on the rostrum represent highly innervated, ampullary electroreceptors and that both species are correspondingly sensitive to weak electric fields. In the present study, for a comparative assessment of the sensitivity of the bottlenose dolphin's electroreceptive system, we determined detection thresholds for DC and AC electric fields with two bottlenose dolphins. In a psychophysical experiment, the animals were trained to respond to electric field stimuli using the go/no-go paradigm. We show that the two bottlenose dolphins are able to detect DC electric fields as low as 2.4 and 5.5 µV cm−1, respectively, a detection threshold in the same order of magnitude as those in the platypus and the Guiana dolphin. Detection thresholds for AC fields (1, 5 and 25 Hz) were generally higher than those for DC fields, and the sensitivity for AC fields decreased with increasing frequency. Although the electroreceptive sensitivity of dolphins is lower than that of elasmobranchs, it is suggested that it allows for both micro- and macro-scale orientation. In dolphins pursuing benthic foraging strategies, electroreception may facilitate short-range prey detection and target-oriented snapping of their prey. Furthermore, the ability to detect weak electric fields may enable dolphins to perceive the Earth's magnetic field through induction-based magnetoreception, thus allowing large-scale orientation. --------------------- The paper is open access and be downloaded here: https://doi.org/10.1242/jeb.245845 Please feel free to reach out with any questions (tim.huettne...@gmail.com) Best regards, Tim Hüttner
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