Song complexity is maintained during inter-population cultural transmission of humpback whale songs

Abstract

Among animal species, the songs of male humpback whales (Megaptera novaeangliae) are a rare example of social learning between entire populations. Understanding fine-scale similarity in song patterns and structural features will better clarify how accurately songs are learned during inter-population transmission. Here, six distinct song types (2009–2015) transmitted from the east Australian to New Caledonian populations were quantitatively analysed using fine-scale song features. Results found that New Caledonian whales learned each song type with high accuracy regardless of the pattern’s complexity. However, there were rare instances of themes (stereotyped patterns of sound units) only sung by a single population. These occurred more often in progressively changing ‘evolutionary’ songs compared to rapidly changing ‘revolutionary’ songs. Our results suggest that populations do not need to reduce complexity to accurately learn song patterns. Populations may also incorporate changes and embellishments into songs in the form of themes which are suggested to be learnt as distinct segments. Maintaining complex song patterns with such accuracy suggests significant acoustic contact, supporting the hypothesis that song learning may occur on shared feeding grounds or migration routes. This study improves the understanding of inter-population mechanisms for large-scale cultural transmission in animals.

Changes in humpback whale song structure and complexity reveal a rapid evolution on a feeding ground in Northern Norway

“…The number of units per song as well as the closely linked variable of song duration appeared to be the main causes for the higher song complexity in the present study. Allen et al (2022) reported similar observations, suggesting that these changes are presumably copy errors or flexibility within song elements (e.g. unit repetition) used by the singers.…”

“…If the ability to rapidly adopt changes within the song demonstrates a higher cognitive ability in humpback whales, and with females selecting for this trait, then the content of the song itself may be less meaningful. Thus, it might rather be the learning ability of the singer that increases its reproductive chances Allen et al, 2022). It remains unclear, however, whether processes of mate selection can explain why humpback whales constantly modify their songs over time, and whether females prefer males with larger song repertoires.…”

“…Song learning is most likely facilitated through contact of different breeding populations on feeding grounds or overlapping migration routes, representing a potential mechanism of song transmission (Garland et al, 2011;Garland et al, 2013a;Garland et al, 2013b;Allen et al, 2022;Schulze et al, 2022). The rather extensive modifications in some themes between the years (e.g.…”

“…Song transfer between male humpback whales is hypothesized to occur when individuals are in acoustic contact; one of the possible mechanisms might be when different breeding populations geographically overlap on a shared feeding ground (Payne and Guinee, 1983;Garland et al, 2013a;Allen et al, 2022;Schulze et al, 2022). Humpback whales typically undertake extensive annual migrations (ca.…”

An examination of the educational and instructional facets in isiXhosa children’s oral songs

“…Traditional societies often use songs and music to pass down historical and cultural knowledge from one generation to the next. Children's songs may celebrate important events, such as harvests or festivals, or convey messages about respect for parents and grandparents, community values, and other important social norms (Allen et al, 2022). By learning these songs, children develop a deeper understanding and veneration of their ethnic heritage and the social world concerning them.…”