Sperm whales use their gigantic nose to produce the most powerful sounds in the animal kingdom, presumably to echolocate deep-sea prey at long ranges and possibly to debilitate prey. To test these hypotheses, we deployed sound recording tags (DTAG-4) on the tip of the nose of three sperm whales. One of these recordings yielded over 6000 echo streams from organisms detected up to 144 m ahead of the whale, supporting a long-range prey detection function of the sperm whale biosonar. The whale navigated this complex acoustic scene by maintaining a stable, long-range acoustic gaze suggesting continual resource evaluation. Less than 10% of the echoic organisms recorded by the tag were targeted for capture and only 18% of the buzzes were emitted within the 50 m depth interval of maximum organism encounter rate, demonstrating echo-guided prey selection. Buzzes were initiated more than 20 m from the prey, showing that sperm whales do not debilitate their prey with sound, but trade echo levels for reduced forward masking and rapid updates on prey location in keeping with the lower manoeuvrability of these large predators. We conclude that the powerful biosonar of sperm whales enables long-range echolocation and selection of prey, but not acoustic debilitation.

抹香鲸用它们巨大的鼻子发出动物王国中最强大的声音，大概是为了远距离回声定位深海猎物，并可能使猎物虚弱。为了验证这些假设，我们在三头抹香鲸的鼻尖部署了录音标签 (DTAG-4)。其中一个记录产生了超过 6000 条来自在鲸鱼前方 144 m 处检测到的生物体的回波流，支持抹香鲸生物声纳的远程猎物检测功能。鲸鱼通过保持稳定的远距离声学凝视在这个复杂的声学场景中导航，这表明持续的资源评估。标签记录的回声生物中只有不到 10% 被作为捕获目标，只有 18% 的嗡嗡声在最大生物遇到率的 50 m 深度间隔内发出，表明回声引导猎物选择。嗡嗡声是在距猎物 20 m 以上的地方发出的，这表明抹香鲸不会用声音削弱猎物，而是用回声水平来减少前向掩蔽和快速更新猎物位置，从而与这些大型捕食者的低机动性保持一致。我们得出的结论是，抹香鲸强大的生物声纳能够实现远距离回声定位和猎物选择，但不能使声学衰弱。