Walmsley Sam F, Rendell Luke, Hussey Nigel E, Marcoux Marianne
Sea Mammal Research Unit, School of Biology, University of St Andrews, Sir Harold Mitchell Building, St Andrews, KY16 9TH, Scotland.
Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada.
J Acoust Soc Am. 2020 Feb;147(2):1078. doi: 10.1121/10.0000671.
Sequences are indicative of signal complexity in vocal communication. While vocal sequences are well-described in birds and terrestrial mammals, the extent to which marine mammals use them is less well understood. This study documents the first known examples of sequence use in the narwhal (Monodon monoceros), a gregarious Arctic cetacean. Eight female narwhals were fitted with animal-borne recording devices, resulting in one of the largest datasets of narwhal acoustic behaviour to date. A combination of visual and quantitative classification procedures was used to test whether subjectively defined vocalization patterns were organized into sequences. Next, acoustic characteristics were analyzed to assess whether sequences could disclose group or individual identity. Finally, generalized linear models were used to investigate the behavioural context under which sequences were produced. Two types of sequences, consisting of "paired" patterns and "burst pulse series," were identified. Sequences of burst pulse series were typically produced in periods of high vocal activity, whereas the opposite was true for sequences of paired patterns, suggesting different functions for each. These findings extend the set of odontocetes which are known to use vocal sequences. Inquiry into vocal sequences in other understudied marine mammals may provide further insights into the evolution of vocal communication.
序列表明了声音交流中的信号复杂性。虽然鸟类和陆生哺乳动物的声音序列已有详细描述，但对海洋哺乳动物使用声音序列的程度了解较少。本研究记录了独角鲸（Monodon monoceros）——一种群居的北极鲸类动物——首次已知的声音序列使用实例。八头雌性独角鲸被安装了动物携带式记录设备，从而得到了迄今为止最大的独角鲸声学行为数据集之一。采用视觉和定量分类程序相结合的方法，来测试主观定义的发声模式是否被组织成序列。接下来，分析声学特征以评估序列是否能揭示群体或个体身份。最后，使用广义线性模型来研究产生序列的行为背景。识别出了两种类型的序列，即由“配对”模式和“脉冲串系列”组成的序列。脉冲串系列序列通常在高声活动期产生，而配对模式序列则相反，这表明每种序列具有不同的功能。这些发现扩展了已知使用声音序列的齿鲸类动物范围。对其他研究较少的海洋哺乳动物的声音序列进行探究，可能会为声音交流的进化提供进一步的见解。
