Acoustic structure and variation in mountain and western gorilla close calls: a syntactic approach
Acoustic structure and variation in mountain and western gorilla close calls: a syntactic approach
复制标题
DOI：
10.1163/1568539x-00003175
复制
发表时间：
2014-01-01
期刊：
影响因子：
1.3
通讯作者：
Boesch, Christophe
中科院分区：
文献类型：
--
作者：
Hedwig, Daniela;Hammerschmidt, Kurt;Boesch, Christophe
通过研究声学变异和使用基于声学结构的客观分类方案，可以大大提高我们对一个物种发声功能的理解。在这里，我们使用的句法方法来研究大猩猩近距离发声（近距离叫声）的声学结构，这仍然是鲜为人知的。我们研究了来自乌干达Bwindi Impenetrable国家公园的10只山地大猩猩（Gorilla beringei beringei）和来自中非共和国Bai Hokou的5只西部低地大猩猩（Gorilla gorilla gorilla）的2130种叫声。我们使用不同的声学特征将呼叫分割成单元，并采用基于模型的聚类分析来定义单元类型的库。然后，我们研究了如何将单元类型组合到调用中。最后，我们比较了年龄性别类和两个研究组之间的单位类型的使用。我们发现，大猩猩的近距离叫声由5个整合的声学单元类型组成，这些声学单元类型灵活但非随机地连接成159种组合。我们的研究结果是符合以往的定量声学分析表明，在各种动物的声乐曲目，特别是近距离发声的声学变化程度很高。我们的研究结果补充了（1）最近的论点，即将声乐曲目描述为离散或分级的常见做法可能没有什么价值，因为这种区分可能是由人类感知和声乐曲目的非定量描述驱动的，以及（2）最近的研究表明，近距离社交呼叫的灵活性可以通过组合系统来实现，以前主要是在长距离发声中进行研究。此外，我们的研究强调了西部和山地大猩猩的声音库的差异，正如预期的那样，考虑到环境和社会行为的差异。我们的研究结果为进一步深入研究大猩猩近距离叫声的功能提供了机会，这将有助于更全面地了解猿类的声音交流。
Our understanding of the functioning of a species' vocal repertoire can be greatly improved by investigating acoustic variation and using objective classification schemes based on acoustic structure. Here we used a syntactic approach to investigate the acoustic structure of the gorilla close distance vocalizations ('close calls'), which remain as yet little understood. We examined 2130 calls of 10 mountain gorillas (Gorilla beringei beringei) from Bwindi Impenetrable National Park, Uganda, and 5 western lowland gorillas (Gorilla gorilla gorilla) from Bai Hokou, Central African Republic. We segmented calls into units using distinct acoustic features and employed model-based cluster analyses to define the repertoire of unit types. We then examined how unit types were combined into calls. Lastly, we compared unit type use between age sex classes and the two study groups. We found that the gorilla close calls consist of 5 intergraded acoustic unit types which were flexibly but yet non-randomly concatenated into 159 combinations. Our results are in line with previous quantitative acoustic analyses demonstrating a high degree of acoustic variation in a variety of animal vocal repertoires, particularly close distance vocalizations. Our findings add on to (1) the recent argument that the common practice of describing vocal repertoires as either discrete or graded may be of little value as such distinctions may be driven by human perception and non-quantitative descriptions of vocal repertoires, and (2) recent studies indicating that flexibility in close range social calls can come about through combinatorial systems, which previously have been studied primarily in long distance vocalizations. Furthermore, our study highlights differences in the vocal repertoire of western and mountain gorillas, as expected given differences in environment and social behaviour. Our results offer opportunities for further in-depth studies investigating the function of the gorilla close calls, which will contribute to a more comprehensive understanding of ape vocal communication in general.