Nieder Carolin, Parmentier Eric, Jeffs Andrew G, Radford Craig
Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Morphologie Fonctionnelle et Evolutive, Université de Liège, Liège, Belgium.
R Soc Open Sci. 2025 Mar 26;12(3):242212. doi: 10.1098/rsos.242212. eCollection 2025 Mar.
Elasmobranchs are an evolutionarily ancient group of cartilaginous fishes that can hear underwater sounds but are not historically viewed as active sound producers. Three recent reports of several species of rays producing clicks in response to approaching divers have cast doubt on this long prevailing view and resulted in calls for more research into sound production in elasmobranchs. This study shows that the rig, , produces clicks (mean SPL = 156.3 dB re. 1 μPa ± 0.9 s.e.m. at approx. 30 cm) when handled underwater, representing the first documented case of deliberate sound production by a shark. Clicks were broadband (mean bandwidth = 23 kHz ± 0.1 s.e.m.), with peak energies between 2.4 and 18.5 kHz (mean peak frequency = 9.6 kHz ± 0.3 s.e.m.), and mean duration of 48.42 ms ± 2.9 s.e.m. Clicks contained considerably less energy in frequencies below 1 kHz, which overlap with the hearing range of the rig. We propose that forceful snapping of flattened teeth may be the sound producing mechanism based on the plated tooth morphology and the acoustic characteristics of these clicks. Further behavioural studies are needed to test whether clicks are incidental to the handling or a natural acoustic response of behavioural significance.
板鳃亚纲动物是一类进化历史悠久的软骨鱼类，它们能够在水下听到声音，但在历史上并不被视为活跃的声音生产者。最近有三份报告称，几种鳐鱼在回应靠近的潜水者时会发出咔嗒声，这对这一长期以来盛行的观点提出了质疑，并引发了对板鳃亚纲动物发声研究的更多呼吁。这项研究表明，这种鳐鱼在水下被处理时会发出咔嗒声（在约30厘米处，平均声压级 = 156.3分贝，相对于1微帕 ± 0.9标准误），这是有记录的首例鲨鱼故意发声的情况。咔嗒声是宽带的（平均带宽 = 23千赫 ± 0.1标准误），峰值能量在2.4至18.5千赫之间（平均峰值频率 = 9.6千赫 ± 0.3标准误），平均持续时间为48.42毫秒 ± 2.9标准误。在低于1千赫的频率中，咔嗒声包含的能量要少得多，而这个频率范围与这种鳐鱼的听力范围重叠。基于这种鳐鱼扁平牙齿的形态以及这些咔嗒声的声学特征，我们推测有力地咬合扁平牙齿可能是发声机制。需要进一步的行为研究来测试这些咔嗒声是处理过程中的偶然现象还是具有行为意义的自然声学反应。
