Note Repertoire and Age-sex Differences in the Vocalizations of Sapajus libidinosus

AbstractDocumenting the size and variety of a species’ vocal and note repertoires is fundamental for a better understanding of the diversity, function, and importance of primate calls. Sapajus libidinosus is widely known for its cognitive complexity, including tool use, and is therefore expected to present a large and complex acoustic repertoire. We describe the acoustic communication of S. libidinosus and test for differences in vocal parameters between contexts, sexes, and developmental stages. We also present the species’ note repertoire and its acoustic parameters. We recorded and extracted spectral and temporal parameters of 265 calls, with the sender’s sex and developmental stage, and the context of call emission. We identified 16 calls composed of eight different notes, with four calls presenting a combination of different notes. Juveniles presented calls with higher frequency and shorter duration than adults. Males presented calls with higher frequency and longer duration than females. These differences in acoustic proprieties may relate to traits, such as body size, and social roles. The use of the same note in different calls could represent an important evolutionary strategy in primates, allowing the creation of multiple calls without mechanical or neurological constraints. This understanding of note use, and its apparent combinatorial patterns, provides the foundation for future investigations of whether the underlying patterns indicate syntactic rules and whether they convey complex semantic information.DOI: 10.1007/s10764-025-00513-2摘要 记录某一物种的发声库与音节库的规模与多样性，是深入理解灵长类叫声多样性、功能与重要性的基础。白额卷尾猴（Sapajus libidinosus）以其包括工具使用在内的认知复杂性而广为人知，因此被推测拥有规模庞大且结构复杂的声学发声库。本研究对S. libidinosus的声学通讯行为进行描述，并检验不同场景、性别与发育阶段下的发声参数差异，同时梳理了该物种的音节库及其声学参数。 本研究共录制并提取了265次叫声的频谱与时域参数，同时记录了发声个体的性别、发育阶段以及叫声发出的场景。研究共识别出16种叫声，由8种不同音节构成，其中4种叫声由不同音节组合而成。幼年个体的叫声频率高于成年个体，且时长更短；雄性个体的叫声频率高于雌性个体，且时长更长。这些声学特性的差异可能与体型、社会角色等特征相关。在不同叫声中复用同一音节，可能是灵长类的一项重要进化策略，使其能够在不受机械或神经约束的前提下生成多种不同叫声。本次研究对音节复用及其明显组合模式的认知，为后续探究潜在模式是否体现句法规则、是否能够传递复杂语义信息奠定了基础。 DOI: 10.1007/s10764-025-00513-2