Most dolphin species produce broadband clicks for echolocation (i.e., biosonar pulses), and whistles and burst-pulsed calls for communication purposes. A few dolphin species in the southern hemisphere are reported to only produce clicks of a more narrowband high-frequency (NBHF) type, very similar to the clicks produced by porpoises. Here, we use underwater acoustic recordings of Peale's dolphins () in the Falkland Islands to show that they also can produce broadband clicks and tonal whistle sounds similar to other whistling odontocete species in addition to NBHF clicks. Whistles and broadband clicks co-occurred in seven out of twelve acoustic encounters with Peale's dolphins. The co-occurrence of whistles and broadband signals, which were predominately burst-pulses, produced by Peale's dolphins in this study points to a probable function as communication signals. Furthermore, the measured frequency and time parameters of Peale's dolphin whistles were comparable with whistles recorded from four additional species in the genus in various parts of their ranges. This is the only species of recorded to date that can relax acoustic crypsis in a similar manner as Heaviside's (), Commerson's (), and Hector's () dolphins. Our findings make it likely that additional NBHF species have the ability to generate both pulsed signal types and whistles, and further challenges the acoustic classification of NBHF species.

中文翻译：

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皮尔氏海豚（Lagenorhynchus australis）是海豚和鼠海豚的声学融合体

大多数海豚物种会产生用于回声定位的宽带喀哒声（即生物声纳脉冲），并产生用于通信目的的口哨声和突发脉冲叫声。据报道，南半球的一些海豚物种仅产生更窄带高频（NBHF）类型的滴答声，与鼠海豚产生的滴答声非常相似。在这里，我们使用福克兰群岛皮尔海豚 (Peale's dolphin) 的水下声学记录表明，除了 NBHF 滴答声之外，它们还可以发出与其他齿鲸物种类似的宽带滴答声和音调哨声。在与皮尔海豚的十二次声音接触中，有七次同时出现口哨声和宽频咔哒声。在这项研究中，皮尔海豚产生的口哨声和宽带信号（主要是突发脉冲）同时出现，表明它们可能具有通信信号的功能。此外，测量到的皮尔海豚哨声的频率和时间参数与该属另外四个物种在其分布范围的不同部分记录的哨声具有可比性。这是迄今为止记录到的唯一一种能够以与海维赛海豚、科默森海豚和赫克托海豚类似的方式放松声学隐匿的物种。我们的研究结果表明，其他 NBHF 物种可能具有产生脉冲信号类型和哨声的能力，并进一步挑战了 NBHF 物种的声学分类。