Mooney T Aran, Kaplan Maxwell B, Lammers Marc O
Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA, USA
Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA, USA.
Biol Lett. 2016 Nov;12(11). doi: 10.1098/rsbl.2016.0381.
Acoustic signals are fundamental to animal communication, and cetaceans are often considered bioacoustic specialists. Nearly all studies of their acoustic communication focus on sound pressure measurements, overlooking the particle motion components of their communication signals. Here we characterized the levels of acoustic particle velocity (and pressure) of song produced by humpback whales. We demonstrate that whales generate acoustic fields that include significant particle velocity components that are detectable over relatively long distances sufficient to play a role in acoustic communication. We show that these signals attenuate predictably in a manner similar to pressure and that direct particle velocity measurements can provide bearings to singing whales. Whales could potentially use such information to determine the distance of signalling animals. Additionally, the vibratory nature of particle velocity may stimulate bone conduction, a hearing modality found in other low-frequency specialized mammals, offering a parsimonious mechanism of acoustic energy transduction into the massive ossicles of whale ears. With substantial concerns regarding the effects of increasing anthropogenic ocean noise and major uncertainties surrounding mysticete hearing, these results highlight both an unexplored pathway that may be available for whale acoustic communication and the need to better understand the biological role of acoustic particle motion.
声学信号是动物交流的基础，鲸类动物常被视为生物声学专家。几乎所有关于它们声学交流的研究都集中在声压测量上，而忽略了其交流信号中的质点运动成分。在此，我们对座头鲸歌声的声学质点速度（和声压）水平进行了表征。我们证明，鲸鱼产生的声场包含显著的质点速度成分，这些成分在相对较长的距离内都能被检测到，足以在声学交流中发挥作用。我们表明，这些信号的衰减方式与声压类似，可以预测，并且直接测量质点速度能够为正在唱歌的鲸鱼提供方位信息。鲸鱼有可能利用此类信息来确定信号发出动物的距离。此外，质点速度的振动特性可能会刺激骨传导，这是在其他低频特化哺乳动物中发现的一种听觉方式，为声学能量转化为鲸鱼耳朵中的巨大听小骨提供了一种简洁的机制。鉴于人们对日益增加的人为海洋噪声的影响以及须鲸听力方面的主要不确定性深感担忧，这些结果凸显了一条可能可供鲸鱼进行声学交流的未被探索的途径，以及更好地理解声学质点运动的生物学作用的必要性。
