The humpback whale, often called the “singer of the sea,” produces complex and haunting vocalizations. These sounds are highly organized acoustic displays that travel vast distances underwater. Understanding what a humpback whale sounds like requires recognizing the distinct and sophisticated nature of their acoustic repertoire.
The Two Categories of Humpback Sounds
Scientists divide humpback vocalizations into two principal categories: the highly structured “Song” and the simpler, varied “Non-Song Vocalizations,” or calls. The song is a long, patterned sequence of sounds produced almost exclusively by males, primarily on tropical breeding grounds in winter. This complex performance contrasts sharply with calls, which are short, discrete sounds used in different contexts throughout the year.
The differences in context and structure suggest distinct functions for each category. While the intricate song is a seasonal phenomenon, non-song calls are heard across the entire migratory range, including cold-water feeding areas. Calls lack the repeating, predictable structure of the song and are typically shorter in duration.
Anatomy of the Humpback Song
The humpback song is one of the most complex and longest vocalizations in the animal kingdom, often lasting between five and 30 minutes and sometimes repeated continuously for more than 24 hours. The song possesses a distinct hierarchical structure, which has been compared to human musical traditions. The foundation is the “unit,” the shortest uninterrupted sound akin to a musical note, which can include whoops, moans, cries, or squeals.
A sequence of several units forms a “phrase,” which a whale typically repeats for a few minutes. Multiple phrases repeated in a specific pattern then form a “theme.” The complete song is constructed from a sequence of two to nine themes, which are sung in a specific, ordered cycle before the whale returns to the beginning.
All males within a single population, such as those in an ocean basin, sing the same current version of the song at any given time. This shared song gradually evolves over the breeding season and from year to year, a process known as cultural transmission. The song’s frequency range fluctuates between 20 Hertz and 24,000 Hertz, and it can be loud enough to be detected up to 160 kilometers away in ideal conditions.
Social and Feeding Calls
Distinct from the elaborate song, non-song vocalizations are shorter, less-patterned sounds used in day-to-day social interactions and foraging activities. These calls are produced by both male and female humpbacks year-round and lack the strict, repeating structure of the song. The acoustic characteristics of these calls are stable, with many types persisting across multiple generations.
Examples of these functional calls include “grunts,” “groans,” “thwops,” and “snorts,” which are associated with immediate communication needs. A well-studied example is the “feeding call,” a long sound of near-constant frequency produced during cooperative foraging behaviors, such as bubble-net feeding. This loud, intense call is hypothesized to coordinate the group’s movements or to startle schools of fish into tighter aggregations, making them easier to capture. Humpbacks also generate sounds by physically slapping their tail flukes or pectoral fins against the water’s surface, creating percussive, broadband sounds.
The Purpose Behind the Vocalizations
The precise function of the complex song remains a subject of ongoing scientific investigation, though the most widely accepted theory focuses on reproductive displays. Because songs are predominantly sung by males on the breeding grounds, they are thought to attract females or signal fitness to potential mates. The continuous repetition and complexity may also serve as a form of male-to-male communication, potentially establishing dominance hierarchies or sizing up rivals.
For non-song vocalizations, the purposes are more directly linked to immediate behavioral context. Calls are used for maintaining group cohesion, especially among cow-calf pairs, and for coordinating movements during activities like migration or feeding. For instance, a mother and calf use calls to communicate and locate each other. Non-song calls are also observed in aggressive encounters between competing males and may function as warning signals or contact calls.