During the Cold War the US Navy laid lines of hydrophones across the floors of the world’s oceans to listen for Soviet submarines. The network, called SOSUS, was very good at hearing large, low-pitched things a long way off, and whales are large, low-pitched things. When the Cold War ended the Navy began opening the system to scientists. A Navy researcher invited William Watkins, an acoustics specialist at Woods Hole Oceanographic Institution in Massachusetts, to use it, and Watkins saw that he could follow blue, fin and humpback whales through their seasons.
What was heard
One voice did not fit. A call with most of its energy between about 50 and 52 hertz was first noticed in 1989, and from 1992 Watkins’s team was tracking it every year. Leslie Jamison, who reported the story for The Atavist in 2014, describes Navy technicians at Whidbey Island in Washington State stretching the signal out on a spectrogram, recognizing the rhythm of a whale and realizing the pitch was wrong. Blue whales sing far lower, mostly below 20 hertz, and fin whales sit around 20. This one sang roughly where the lowest note of a tuba sits, well above both.
The investigation
Watkins, his former research assistant Mary Ann Daher and two colleagues published twelve years of tracks in Deep-Sea Research in December 2004. They had found no other call like it on any hydrophone system in the North Pacific. Only one series of these calls was ever recorded at a time, with no overlap, which pointed to a single animal. The calls came between August and February, mostly in December and January. Its seasonal routes changed from year to year, from short meanders to long runs west to east or north to south, covering between about 700 and 11,000 kilometers at a leisurely 0.7 to 3.8 kilometers an hour. None of it lined up with the blue, fin or humpback whales heard on the same equipment.
The paper was candid about what it did not know. The authors could not name the species and could not say whether they were following a hybrid or simply an unusual individual. Watkins did not see it in print; he died in September 2004, a month after it was accepted, leaving Daher to deal with the response.
The explanations
That response was huge. After a New York Times story that December, letters poured into Woods Hole from people who saw themselves in a whale singing where no one could hear it, including deaf readers who wondered whether it shared their condition. The label of the world’s loneliest whale stuck. Daher was uneasy about it. Speaking to a journalist in 2013, she said nobody knew whether the voice came from a deformity, whether the animal was truly alone, or whether loneliness was even a word that applied.
The physical explanations remain open. The call’s patterns resemble blue whale song, which has led some to suggest an individual with an unusual voice. John Calambokidis, a whale biologist at Cascadia Research Collective, has floated a blue–fin hybrid, which would be plausible: genetic work has found fin whale DNA in the genomes of North Atlantic blue whales. By the time the 2004 paper was finished, the call had slipped slightly lower, toward 50 hertz, as might be expected of a maturing animal. Recordings made off California in 2010 have also been read as a sign that more than one animal may produce such calls.
A 2021 documentary, The Loneliest Whale, followed a privately funded search with scientists and listening devices off California. Its makers concluded that the calls come from more than one whale and filmed what they believed to be a blue–fin hybrid, though the identification has not been confirmed in the scientific literature.
Where it stands
There is no doubt that the sound is biological, that it is a whale, and that for at least twelve years apparently one individual was producing it on its own across a huge stretch of ocean. That much is documented in a peer-reviewed paper built on Navy data. What the animal is, whether it is still alive and whether it has company remain unanswered. Whether it is lonely is a question for people rather than for whales.