接着，我们用一个水下扬声器将电子合成声播放给海豚听，发现它们有强烈的反应。

Then we played it back to the dolphins through an underwater speaker and we found they responded strongly.

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但与人耳可听见的声音相比，鲸鱼更‘擅长’用超声波交流，尤其是在水下。

But whales communicate better through ultrasonic sounds than through human-audible sounds, especially underwater, "he explained."

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儒艮日日夜夜地吃着水下的草料，它们用多刺和敏感的鼻子来翻找，并用粗糙的嘴唇和牙齿反复不断地咀嚼这些草料。

Dugongs graze on underwater grasses day and night, rooting for them with their bristled, sensitive snouts and chomping them with their rough lips.

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