Department of Anthropology, The CUNY Graduate Center, The Graduate Center of the City University of New York, 365 5th Avenue, New York, NY, 10016, USA.
New York Consortium in Evolutionary Primatology, New York, NY, USA.
Primates. 2023 Nov;64(6):621-635. doi: 10.1007/s10329-023-01083-8. Epub 2023 Aug 16.
Ruffed lemurs (Varecia spp.) exhibit a unique suite of behavioral traits compared to other lemur species, which includes their fluid fission-fusion social dynamics, communal rearing of parked litters, and pronounced frugivory in their humid rainforest habitats. Given these traits, and the dense rainforests they inhabit, vocal communication may be key to maintaining social cohesion, coordinating infant care, and/or defending their high-quality food resources. Indeed, they are known for their raucous 'roar-shriek' calls. However, there has been surprisingly little research on vocal communication in Varecia species and only two previously published repertoires, both of which were qualitative descriptions of their calls. In this study, we quantitatively examined the vocal repertoire of wild black-and-white ruffed lemurs (Varecia variegata) at Mangevo, Ranomafana National Park, Madagascar. We characterized 11 call types using 33 bioacoustic parameters related to frequency, duration, tonality, and composition. We also used discriminant function analysis and hierarchical clustering to quantitatively and objectively classify call types within the black-and-white ruffed lemur vocal repertoire. The repertoire consists of both monosyllabic and multisyllabic calls that are individually given or emitted in contagious choruses. Eight of the 11 calls were also used in combination or in larger multi-call sequences. The discriminant function analysis correctly assigned call types with 87% success, though this varied greatly by call type (1-65%). Hierarchical clustering identified 3-4 robust clusters, indicating low clustering structure in the data and suggesting that V. variegata exhibits a graded vocal repertoire. Future work should consider the environmental and behavioral contexts in which calls are used to better understand the function of these call types and combinations.
环尾狐猴（Varecia spp.）与其他狐猴物种相比表现出独特的行为特征组合，包括它们流畅的分裂-融合社会动态、成群抚养已停放的幼崽，以及在潮湿的雨林栖息地中明显的食果行为。鉴于这些特征以及它们栖息的茂密雨林，声音通讯可能是维持社会凝聚力、协调婴儿护理和/或保护其高质量食物资源的关键。事实上，它们以其喧闹的“咆哮尖叫”叫声而闻名。然而，关于环尾狐猴物种的声音通讯研究却少之又少，仅有两项先前发表的曲目，均为它们叫声的定性描述。在这项研究中，我们对马达加斯加 Ranomafana 国家公园 Mangevo 的野生黑白领狐猴（Varecia variegata）的声音曲目进行了定量研究。我们使用与频率、持续时间、音调和组成有关的 33 个生物声学参数来描述 11 种叫声类型。我们还使用判别函数分析和层次聚类来定量和客观地对黑白领狐猴的叫声曲目进行分类。该曲目包含单音节和多音节叫声，它们可以单独发出，也可以在有传染性的合唱中发出。11 种叫声中的 8 种也可以组合或发出更大的多叫声序列。判别函数分析正确分配叫声类型的成功率为 87%，尽管这因叫声类型而异（1-65%）。层次聚类确定了 3-4 个稳健的聚类，这表明数据中的聚类结构较低，并表明 V. variegata 表现出一个渐进的声音曲目。未来的工作应该考虑在环境和行为背景下使用叫声，以更好地理解这些叫声类型和组合的功能。
