Sound is vital for communication and navigation across the animal kingdom and sound communication is unrivaled in accuracy and information richness over long distances both in air and water. The source level (SL) of the sound is a key factor in determining the range at which animals can communicate and the range at which echolocators can operate their biosonar. Here we compile, standardize and compare measurements of the loudest animals both in air and water. In air we find a remarkable similarity in the highest SLs produced across the different taxa. Within all taxa we find species that produce sound above 100 dBpeak re 20 µPa at 1 meter, and a few bird and mammal species have SLs as high as 125 dBpeak re 20 µPa at 1 meter. We next used pulsating sphere and piston models to estimate the maximum sound pressures generated in the radiated sound field. These data suggest that the loudest species within all taxa converge upon maximum pressures of 140-150 dBpeak re 20 µPa in air. In water, the toothed whales produce by far the loudest SLs up to 240 dBpeak re 1 µPa at 1 meter. We discuss possible physical limitations to the production, radiation and propagation of high sound pressures. Furthermore, we discuss physiological limitations to the wide variety of sound generating mechanisms that have evolved in air and water of which many are still not well-understood or even unknown. We propose that in air, non-linear sound propagation forms a limit to producing louder sounds. While nonlinear sound propagation may play a role in water as well, both sperm whale and pistol shrimp reach another physical limit of sound production, the cavitation limit in water. Taken together, our data suggests that both in air and water, animals evolved that produce sound so loud that they are pushing against physical rather than physiological limits of sound production, radiation and propagation.

中文翻译：

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你能走多大声？在动物发声中产生高声压的物理和生理限制

声音对于跨动物界的交流和导航至关重要，而声音交流在空中和水中的长距离上的准确性和信息丰富性无与伦比。声音的源电平（SL）是确定动物可以交流的范围以及回声定位仪可以操作其生物声纳的范围的关键因素。在这里，我们对空气和水中最响亮的动物的测量值进行汇编，标准化和比较。在空中，我们发现在不同分类单元中产生的最高SL有着惊人的相似性。在所有分类单元中，我们发现在1米处产生的声音高于100 dBpeak re 20 µPa的物种，而少数鸟类和哺乳动物物种在1米处的SL高达125 dBpeak re 20 µPa的物种。接下来，我们使用脉动球面和活塞模型来估计在辐射声场中产生的最大声压。这些数据表明，在空气中20 µPa的最大压力为140-150 dBpeakpeak时，所有分类单元中最响亮的物种会聚。在水中，齿鲸在1米处产生的声音最大，最大SL可达240 dBpeak re re 1 µPa。我们讨论了高声压的产生，辐射和传播的可能的物理限制。此外，我们讨论了在空气和水中演化出的多种声音生成机制的生理局限性，其中许多机制仍未得到很好的理解，甚至是未知的。我们建议在空气中，非线性声音传播会限制产生更大声的声音。虽然非线性声音传播也可能在水中起作用，抹香鲸和手枪虾都达到了声音产生的另一个物理极限，即水中的空化极限。综上所述，我们的数据表明，无论是在空气还是水中，动物的进化都会产生很大的声音，以至于它们在声音产生，辐射和传播的物理而非生理极限方面都处于不利地位。