Song Morphing by Humpback Whales: Cultural or Epiphenomenal?

Eduardo Mercado

doi:10.3389/fpsyg.2020.574403

Abstract

Singing humpback whales (Megaptera noavaengliae) collectively and progressively change the sounds and patterns they produce within their songs throughout their lives. The dynamic modifications that humpback whales make to their songs are often cited as an impressive example of cultural transmission through vocal learning in a non-human. Some elements of song change challenge this interpretation, however, including: (1) singers often incrementally and progressively morph phrases within and across songs as time passes, with trajectories of change being comparable across multiple time scales; (2) acoustically isolated subpopulations singing similar songs morph the acoustic properties of songs in similar ways; and (3) complex sound patterns, including phrases, themes, and whole songs, recur across years and populations. These properties of song dynamics suggest that singing humpback whales may be modulating song features in response to local conditions and genetic predispositions rather than socially learning novel sound patterns by copying other singers. Experimental and observational tests of key predictions of these alternative hypotheses are critical to identifying how and why singing humpback whales constantly change their songs.

Highlights

Discussions of animal culture, defined as “shared behavior or information within a community acquired through some form of social learning from conspecifics” (Garland and McGregor, 2020), often highlight the incredible vocal skills of humpback whales (Laland and Janik, 2006; Allen, 2019; Whiten, 2019)
Rendell and Whitehead (2001a) identify humpback whale songs as one of the strongest examples of cetacean culture, a point echoed by Laland and Hoppitt (2003) and Janik (2014)
Payne (2000) compared the process of whale song change to linguistic drift, but much faster, noting that within 1 decade songs produced by a population can change so much that it is not possible to recognize how they relate to earlier versions

Summary

Introduction

Discussions of animal culture, defined as “shared behavior or information within a community acquired through some form of social learning from conspecifics” (Garland and McGregor, 2020), often highlight the incredible vocal skills of humpback whales (Laland and Janik, 2006; Allen, 2019; Whiten, 2019). 99).” Payne and Payne identified one or two shifting themes in recordings from every year they analyzed; suggesting that phrase morphing was a consistent feature of humpback whale songs.

Results

Conclusion