Communication plays a vital role in the social lives of many species and varies greatly in complexity. One possible way to increase communicative complexity is by combining signals into longer sequences, which has been proposed as a mechanism allowing species with a limited repertoire to increase their communicative output. In mammals, most studies on combinatoriality have focused on vocal communication in non-human primates. Here, we investigated a potential combination of alarm calls in the dwarf mongoose (Helogale parvula), a non-primate mammal. Acoustic analyses and playback experiments with a wild population suggest: (i) that dwarf mongooses produce a complex call type (T3) which, at least at the surface level, seems to comprise units that are not functionally different to two meaningful alarm calls (aerial and terrestrial); and (ii) that this T3 call functions as a general alarm, produced in response to a wide range of threats. Using a novel approach, we further explored multiple interpretations of the T3 call based on the information content of the apparent comprising calls and how they are combined. We also considered an alternative, non-combinatorial interpretation that frames T3 as the origin, rather than the product, of the individual alarm calls. This study complements previous knowledge of vocal combinatoriality in non-primate mammals and introduces an approach that could facilitate comparisons between different animal and human communication systems.

中文翻译：

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侏儒猫鼬警报呼叫：调查复杂的非人类动物呼叫

交流在许多物种的社会生活中起着至关重要的作用，并且在复杂性上差异很大。增加交流复杂性的一种可能方法是将信号组合成更长的序列，这已被提议作为一种机制，允许具有有限曲目的物种增加其交流输出。在哺乳动物中，大多数关于组合性的研究都集中在非人类灵长类动物的声音交流上。在这里，我们研究了一种非灵长类哺乳动物侏儒猫鼬（Helogale parvula）的潜在警报组合。野生种群的声学分析和回放实验表明：(i) 侏儒猫鼬产生一种复杂的呼叫类型 (T3)，至少在表面水平，它似乎包含与两个有意义的警报呼叫（空中）在功能上没有区别的单元和地面）；(ii) 此 T3 呼叫用作一般警报，以应对各种威胁。使用一种新颖的方法，我们进一步探索了基于明显包含调用的信息内容以及它们如何组合的 T3 调用的多种解释。我们还考虑了另一种非组合解释，将 T3 视为单个警报呼叫的起源，而不是产品。这项研究补充了之前对非灵长类哺乳动物声音组合的了解，并引入了一种方法，可以促进不同动物和人类交流系统之间的比较。我们进一步探索了基于明显包含调用的信息内容以及它们如何组合的 T3 调用的多种解释。我们还考虑了另一种非组合解释，将 T3 视为单个警报呼叫的起源，而不是产品。这项研究补充了之前对非灵长类哺乳动物声音组合的了解，并引入了一种方法，可以促进不同动物和人类交流系统之间的比较。我们进一步探索了基于明显包含调用的信息内容以及它们如何组合的 T3 调用的多种解释。我们还考虑了另一种非组合解释，将 T3 视为单个警报呼叫的起源，而不是产品。这项研究补充了之前对非灵长类哺乳动物声音组合的了解，并引入了一种方法，可以促进不同动物和人类交流系统之间的比较。