Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33434, USA.
Cornell University, 159 Sapsucker Woods Road, Ithaca, New York 14850, USA.
J Acoust Soc Am. 2020 Mar;147(3):1597. doi: 10.1121/10.0000849.
The vocal repertoire for the Florida manatee is quantitatively categorized from a sample of 1114 calls recorded from 3 different manatee habitats in Florida. First, manatee vocalizations were categorized into five call categories based on visual inspection of spectrograms and following descriptions provided in previous studies. Second, based on measurements of 17 acoustic parameters, the subjective classification scheme was validated using classification and regression trees (CARTs) and model-based cluster analysis paired with silhouette coefficients. CART analysis revealed that these five broad call categories can be successfully distinguished based on correct classification scores of 41.6%-62.5%. Silhouette coefficients determined that the manatee vocal repertoire is highly intergraded. This study supports and expands upon existing subjective categorization schemes by providing a quantifiable methodology for describing the Florida manatees' vocal repertoire. These findings contribute to the increasing number of studies suggesting many animal species vocal repertoires contain graded call types.
对从佛罗里达州 3 个不同的海牛栖息地录制的 1114 个叫声样本进行了定量分类，得到了佛罗里达海牛的叫声曲目。首先，根据声谱图的视觉检查和先前研究中提供的描述，将海牛的叫声分为 5 种叫声类别。其次，基于 17 个声学参数的测量值，使用分类和回归树 (CART) 以及基于模型的聚类分析与轮廓系数，对主观分类方案进行了验证。CART 分析表明，这 5 种广泛的叫声类别可以根据正确分类得分 41.6%-62.5%来成功区分。轮廓系数表明，海牛的叫声曲目高度综合。本研究通过提供一种量化方法来描述佛罗里达海牛的叫声曲目，支持并扩展了现有的主观分类方案。这些发现增加了越来越多的研究表明，许多动物物种的叫声曲目包含分级叫声类型。
