Chapter 22 - Acoustic behavior

Abstract

Bowhead whales (Balaena mysticetus) are the only baleen whale to inhabit the Arctic year-round and are adapted for communicating, navigating, finding mates, and surviving in an environment that is dominated by ice and the polar night. To overcome these challenges, bowheads rely on their sense of sound as the primary modality for these basic life functions. Bowhead behavioral repertoire consists of three major sound categories: calls, gunshots, and song. Calls consist of low-frequency, relatively simple frequency-modulated and amplitude-modulated signals that are produced year-round. Gunshots are less commonly recorded and may be an agonistic display and/or male behavioral display similar to that observed in right whales. Song, which is produced seasonally from approximately November to May, consists of one to three phrase types, each sung repeatedly and in a consistent order. Although this level of song syntax appears to be conserved across years, song composition changes entirely in the types of units and resultant phrases produced over hours, days, and years. It seems particularly noteworthy that bowheads live in an extremely dynamic acoustic environment; their acoustic behavior has evolved to be equally as variable and complex in order to navigate the acoustic ecology of the environment that surrounds them.