Network analysis reveals underlying syntactic features in a vocally learnt mammalian display, humpback whale song

Vocal communication systems have a set of rules that govern the arrangement of acoustic signals, broadly defined as ‘syntax’. However, there is a limited understanding of potentially shared or analogous rules across vocal displays in different taxa. Recent work on songbirds has investigated syntax using network-based modelling. This technique quantifies features such as connectivity (adjacent signals in a sequence) and recurring patterns. Here, we apply network-based modelling to the complex, hierarchically structured songs of humpback whales (Megaptera novaeangliae) from east Australia. Given the song’s annual evolving pattern and the cultural conformity of males within a population, network modelling captured the patterns of multiple song types over 13 consecutive years. Song arrangements in each year displayed clear “small-world” network structure, characterised by clusters of highly connected sounds. Transitions between these connected sounds further suggested a combination of both ...发声通讯系统拥有一套调控声学信号排布的规则，广义上可称之为语法（syntax）。然而，学界对不同分类群（taxa）的发声展示中潜在共享或相似的规则仍缺乏充分认知。近期针对鸣禽的相关研究已通过基于网络的建模方法探究了其语法特征。该技术可量化连通性（序列中相邻的信号）、重复模式等多项特征。本研究将基于网络的建模方法应用于澳大利亚东部海域座头鲸（Megaptera novaeangliae）复杂且具有层级结构的鸣曲。鉴于座头鲸鸣曲的年度演化规律以及种群内雄性个体的文化一致性，该网络建模方法成功捕捉了连续13年间多种鸣曲类型的排布模式。每年的鸣曲排布均呈现出清晰的小世界（small-world）网络结构，其特征为存在大量高连通声学信号集群。这些连通信号间的转换进一步表明，二者兼具……