Vocal learning, the substrate of human language acquisition, has rarely been described in other mammals. Often, group-specific vocal dialects in wild populations provide the main evidence for vocal learning. While social learning is often the most plausible explanation for these intergroup differences, it is usually impossible to exclude other driving factors, such as genetic or ecological backgrounds. Here, we show the formation of dialects through social vocal learning in fruit bats under controlled conditions. We raised 3 groups of pups in conditions mimicking their natural roosts. Namely, pups could hear their mothers' vocalizations but were also exposed to a manipulation playback. The vocalizations in the 3 playbacks mainly differed in their fundamental frequency. From the age of approximately 6 months and onwards, the pups demonstrated distinct dialects, where each group was biased towards its playback. We demonstrate the emergence of dialects through social learning in a mammalian model in a tightly controlled environment. Unlike in the extensively studied case of songbirds where specific tutors are imitated, we demonstrate that bats do not only learn their vocalizations directly from their mothers, but that they are actually influenced by the sounds of the entire crowd. This process, which we term “crowd vocal learning,” might be relevant to many other social animals such as cetaceans and pinnipeds.

声音学习是人类语言习得的基础，但在其他哺乳动物中却很少被描述。通常，野生种群中特定群体的方言为声音学习提供了主要证据。虽然社会学习通常是这些群体间差异最合理的解释，但通常不可能排除其他驱动因素，例如遗传或生态背景。在这里，我们展示了果蝠在受控条件下通过社交声音学习形成方言的过程。我们在模仿它们自然栖息地的条件下饲养了 3 组幼崽。也就是说，幼崽可以听到母亲的声音，但也会受到操纵回放的影响。 3 个回放中的发声主要在基频上有所不同。从大约 6 个月大起，幼崽就表现出不同的方言，每组都偏向于其播放的内容。我们通过在严格控制的环境中的哺乳动物模型中的社会学习来证明方言的出现。与模仿特定导师的鸣禽的广泛研究案例不同，我们证明蝙蝠不仅直接从母亲那里学习发声，而且实际上受到整个人群声音的影响。这个过程，我们称之为“群体发声学习”，可能与许多其他社会动物有关，例如鲸目动物和鳍足类动物。