To the beat of a different drummer: Defining the rhythmic traits of humpback whale vocalizations

Abstract

Tonal signals are useful in behavioral studies as they often represent the building blocks of more complex vocalizations. Their simple structure can be indicative of fundamental processes such as resonant chamber size. Repetitive tones produced by the humpback whales from the Colombian breeding ground are not easily categorized into song nor social calls. These tones display a strong rhythmic quality, yet little is known about the functionality of temporal patterning in its vocalizations. Studies on the temporal structure of song have noted that unit-to-unit duration is relatively consistent within a phrase but that rhythm in song often lacks precision. Taking a musicological approach, we examined potential carrier signals of information within the tones by comparing its rhythmic qualities to those found in social calls (particularly feeding calls) and song, and theorize how rhythmic characteristics may aid the whale in its feeding, communication, and mating pursuits.