Stereotypic and complex phrase types provide structural evidence for a multi-message display in humpback whales (Megaptera novaeangliae)

TitleStereotypic and complex phrase types provide structural evidence for a multi-message display in humpback whales (Megaptera novaeangliae)
Publication TypeJournal Article
Year of Publication2018
AuthorsMurray, Anita, Dunlop Rebecca A., Noad Michael J., and Goldizen Anne W.
JournalThe Journal of the Acoustical Society of America
Volume143
Pagination980-994
ISBN Number0001-4966
EndNote Rec Number11958
KeywordsBeaufort Sea, foraging ecology, humpback whales, megaptera-novaeangliae, noise, pinnipeds, signals
Abstract

Male humpback whales produce a mating display called ?song.? Behavioral studies indicate song has inter- and/or intra-sexual functionality, suggesting song may be a multi-message display. Multi-message displays often include stereotypic components that convey group membership for mate attraction and/or male-male interactions, and complex components that convey individual quality for courtship. Humpback whale song contains sounds (?units?) arranged into sequences (?phrases?). Repetitions of a specific phrase create a ?theme.? Within a theme, imperfect phrase repetitions (?phrase variants?) create variability among phrases of the same type (?phrase type?). The hypothesis that song contains stereotypic and complex phrase types, structural characteristics consistent with a multi-message display, is investigated using recordings of 17 east Australian males (8:2004, 9:2011). Phrase types are categorized as stereotypic or complex using number of unit types, number of phrase variants, and the proportion of phrases that is unique to an individual versus shared amongst males. Unit types are determined using self-organizing maps. Phrase variants are determined by Levenshtein distances between phrases. Stereotypic phrase types have smaller numbers of unit types and shared phrase variants. Complex phrase types have larger numbers of unit types and unique phrase variants. This study supports the hypothesis that song could be a multi-message display.