Global cultural evolutionary model of humpback whale song evolution, revolution and transmission

• Main Authors: Cultural Evolution Society 2021 2021, Zandberg, Lies
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Pacific; Humpback Whale
• Online Access: https://dx.doi.org/10.48448/7ag6-fd22; https://underline.io/lecture/21922-global-cultural-evolutionary-model-of-humpback-whale-song-evolution,-revolution-and-transmission

Humpback whale song is an extraordinary example of vocal cultural behaviour. Within a population all males conform to a common song type. In Northern Hemisphere populations, the complex songs show long-lasting traditions that slowly evolve, while in the South Pacific, population songs are rapidly replaced by a different song adopted from a neighbouring population. The processes underlying these patterns of cultural transmission of songs are not currently understood: the whales’ exceptional size and long-distance migrations make it implausible to experimentally study development. Instead, here we used individual-based models of the entire Southern and Northern Hemisphere humpback whale populations in combination with empirical data to infer the processes of vocal learning and cultural evolution. We simulated processes of song innovation and patterns of contact among populations and compared our model outcomes with patterns of song theme sharing measured in South Pacific populations. We found that low levels of mutation in combination with rare interactions between populations were sufficient to closely fit the pattern of song sharing in the South Pacific, including the distinctive pattern of West-to-East song revolutions. Moreover, the same learning parameters that gave rise to revolutions in the Southern Hemisphere simulations also gave rise to patterns of song evolution in the Northern Hemisphere populations. This study demonstrates how cultural evolutionary approaches can be used to make inferences about the processes underlying cultural transmission.