The sonic signature is that of a whale, albeit at a unique frequency. At 52 hertz, it is just higher than the lowest note on a tuba.[4] The call patterns resemble neither blue nor fin whales, being much higher in frequency, shorter, and more frequent.[5] Blue whales usually vocalize at 10–39 Hz,[2] fin whales at 20 Hz.[1] The 52-hertz calls of this whale are highly variable in their pattern of repetition, duration, and sequence, although they are identifiable easily due to their frequency and characteristic clustering.[6] They have deepened slightly since 1992, suggesting the whale has grown or matured.[5]
The track of the 52-hertz whale is unrelated to the presence or movement of other whale species.[4] Its movements have been somewhat similar to that of blue whales, but its timing has been more like that of fin whales.[6] It is detected in the Pacific Ocean every year beginning in August–December, and moves out of range of the hydrophones in January–February. It travels as far north as the Aleutian and Kodiak Islands, and as far south as the California coast, swimming between 30 and 70 km each day. Its (recorded) distance traveled per season has ranged from a low of 708 km to a high of 11,062 km in 2002–03.[7]
Scientists at the Woods Hole Oceanographic Institution have been unable to identify the species of the whale. They speculate that it could be malformed, or a hybrid of a blue whale and another species.[4] The research team has been contacted by deaf people who believe the whale may be deaf.[4]
Whatever biological cause underlies its unusually high voice does not seem to be detrimental to its survival. The fact that the whale has survived and apparently matured indicates it is probably healthy. Still, its unique call is the only one of its kind detected anywhere and there is only one such source per season.[7] Because of this, the animal has been called the loneliest whale in the world.[5][8][9]