Analysis of the 'Bio-Duck' Sound Reveals Coordinated Underwater Communication in the Southern Ocean

A recent archival analysis, finalized in late 2024, has shed new light on an anomalous sound known as the 'Bio-Duck.' This signal, which has been recorded in Antarctic waters since the 1960s, exhibits a highly structured, alternating pattern strongly indicative of dialogue. For nearly six decades, this recurring acoustic signature remained one of the Southern Ocean's most perplexing mysteries, first documented by underwater observers almost sixty years ago.

Initial theories suggested a man-made origin, perhaps linked to submarine activity. However, the intricate and repetitive nature of the pattern soon cast doubt on these assumptions, prompting researchers to pivot toward a biological source. The complexity of the signal simply did not align with typical mechanical noise.

Acoustic arrays deployed across vast distances detected multiple sound sources. Crucially, researchers determined that one source would emit the signal while the others remained silent until the first concluded, providing compelling evidence of coordinated communication. Ross Chapman, a researcher from the University of Victoria who has been studying the data since 1986, remarked that the most astonishing aspect was the turn-taking: "When one speaker was talking, the others were quiet, as if they were listening." This observation, presented at the 187th Meeting of the Acoustical Society of America (ASA) in November 2024, marks the first indication that these sounds might constitute a conversation between individuals. The study identified at least four distinct 'speakers' producing this sound from various points across the ocean.

While the Antarctic minke whale (Balaenoptera bonaerensis) remains the leading candidate for the sound's origin, the complex acoustic behavior introduces a new layer of intrigue to deep-sea biology as of early 2026. Scientists, including Denise Risch from NOAA, had previously presented strong evidence supporting the minke whale hypothesis in 2014, based on acoustic recorder data attached to whales in February 2013. Establishing the Antarctic minke whale as the source is vital for accurately assessing the species' seasonal presence, migratory routes, and population size, given that acoustic surveys are far more cost-effective than visual monitoring.

The 'Bio-Duck' sound itself occupies a frequency range spanning from 60 Hz up to 100 Hz, with harmonics extending to 1 kHz. The interval between individual sounds typically falls between 1.6 and 3.1 seconds. Earlier speculation linked these sounds to navigation within heavily iced areas. However, this theory was effectively debunked when the sounds were subsequently detected in ice-free, lower latitudes, such as off the coast of Namibia and within the Perth Canyon.

Further research, including studies conducted in 2020, continued to classify these vocalizations, distinguishing between Type C and Type D sounds. A recent discovery published in the journal Biology Letters is reshaping our understanding of Antarctic minke whale vocalizations; it turns out these whales produce more than just their well-known 'boings,' but also these rhythmic pulses. Although the source is now generally established, the precise function of this communication remains an active area of scientific inquiry. One prevailing hypothesis suggests a role in mating, as the peaks in acoustic activity have been observed to coincide with the whales' breeding season in lower latitudes.