Herbst Christian T, Tokuda Isao T, Nishimura Takeshi, Ternström Sten, Ossio Vicky, Levy Marcelo, Fitch W Tecumseh, Dunn Jacob C
Department of Behavioral and Cognitive Biology, University of Vienna , Vienna, Austria.
Center for the Evolutionary Origins of Human Behavior, Kyoto University , Inuyama, Japan.
Philos Trans R Soc Lond B Biol Sci. 2025 Apr 3;380(1923):20240005. doi: 10.1098/rstb.2024.0005.
We investigated the causal basis of abrupt frequency jumps in a unique database of New World monkey vocalizations. We used a combination of acoustic and electroglottographic recordings , excised larynx investigations of vocal fold dynamics, and computational modelling. We particularly attended to the contribution of the vocal membranes: thin upward extensions of the vocal folds found in most primates but absent in humans. In three of the six investigated species, we observed two distinct modes of vocal fold vibration. The first, involving vocal fold vibration alone, produced low-frequency oscillations, and is analogous to that underlying human phonation. The second, incorporating the vocal membranes, resulted in much higher-frequency oscillation. Abrupt fundamental frequency shifts were observed in all three datasets. While these data are reminiscent of the rapid transitions in frequency observed in certain human singing styles (e.g. yodelling), the frequency jumps are considerably larger in the nonhuman primates studied. Our data suggest that peripheral modifications of vocal anatomy provide an important source of variability and complexity in the vocal repertoires of nonhuman primates. We further propose that the call repertoire is crucially related to a species' ability to vocalize with different laryngeal mechanisms, analogous to human vocal registers. This article is part of the theme issue 'Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions'.
我们在一个独特的新世界猴类发声数据库中研究了频率突然跳跃的因果基础。我们结合了声学和电子声门图记录、切除喉部对声带动态的研究以及计算建模。我们特别关注了声膜的作用：声膜是大多数灵长类动物中声带向上的薄延伸部分，但人类没有。在六个被研究物种中的三个物种中，我们观察到了两种不同的声带振动模式。第一种仅涉及声带振动，产生低频振荡，类似于人类发声的基础。第二种模式包含声膜，导致频率高得多的振荡。在所有三个数据集中都观察到了基频的突然变化。虽然这些数据让人联想到在某些人类歌唱风格（如约德尔唱法）中观察到的频率快速转变，但在所研究的非人类灵长类动物中，频率跳跃要大得多。我们的数据表明，发声解剖结构的外周变化是非人类灵长类动物发声库中变异性和复杂性的重要来源。我们进一步提出，叫声库与一个物种用不同喉部机制发声的能力密切相关，类似于人类的声区。本文是主题为“脊椎动物发声中的非线性现象：机制与交流功能”的一部分。
