Gentoo penguins (Pygoscelis papua) react to underwater sounds

Marine mammals and diving birds face several physiological challenges under water, affecting their thermoregulation and locomotion as well as their sensory systems. Therefore, marine mammals have modified ears for improved underwater hearing. Underwater hearing in marine birds have been studied in a few species, but for the record-holding divers, such as penguins, there are no detailed data. We played underwater noise bursts to gentoo penguins (Pygoscelis papua) in a large tank at sound pressure levels between 100 and 120 dB re 1 µPa rms. The penguins showed a graded reaction to the noise bursts, ranging from no reactions at 100 dB to strong reactions in more than 62% of the playbacks at 120 dB re 1 µPa. The responses were always directed away from the sound source. The fact that penguins can detect and react to underwater stimuli may indicate that they make use of sound stimuli for orientation and prey detection during dives. Further, it suggests that penguins may be sensitive to anthropogenic noise, like many species of marine mammals.

海洋哺乳动物与潜水鸟类在水下环境中面临多重生理挑战，这些挑战会对其体温调节、运动能力以及感知系统造成影响。因此，海洋哺乳动物演化出特化的耳部结构，以优化水下听觉功能。目前仅针对少数鸟类物种开展了水下听觉相关研究，但对于企鹅这类深潜纪录保持者，尚缺乏详细的相关数据。本研究在大型水族箱中，以100至120 dB re 1 µPa rms的声压级，向巴布亚企鹅（Pygoscelis papua）播放水下噪声脉冲串。巴布亚企鹅对噪声脉冲串呈现出梯度式反应：在100 dB声压级下无任何反应，而在120 dB声压级下，超过62%的播放试验均引发了强烈反应。所有反应均表现为远离声源的行为。企鹅能够感知水下刺激并做出反应这一事实，表明它们可能在潜水过程中借助声刺激进行定向与猎物搜寻。此外，该结果还提示，与多数海洋哺乳动物物种一样，企鹅可能对人为噪声较为敏感。