Abstract:
Humpback whales (Megaptera novaeangliae) migrate annually between high-latitude summer feeding waters and low-latitude winter mating waters. During migration and in winter waters, adult [male] humpbacks produce long complex songs. Songs gradually change during each singing season, and singers incorporate changes as they occur. Classification of song units using neural networks and cepstral cross correlation reveals that variability in song characteristics within region is lower than variability between regions. These regional differences in song characteristics can be considered to be dialects that are maintained through cultural transmission of regional variants. Thus differences in songs from different regions may be an index of reproductive isolation. Cladistic patterns of geographic and temporal variation in songs support a model of limited migratory exchange among widely separate wintering regions. [Work supported by UARC, SPREP, WDCS, PDCT.]