At first, it sounded like a plot ripped from the pages of a Tom Clancy political thriller. But it turns out the mysterious noise that tormented U.S. diplomats serving in Cuba may have more in common with a David Attenborough nature documentary.
Scientists studying recordings made by diplomats of the unusual high-pitched sounds, which reportedly triggered symptoms such as headaches, nausea and hearing loss for over two years, say the source is the common Caribbean cricket.
"There’s plenty of debate in the medical community over what, if any, physical damage there is to these individuals," Alexander Stubbs of the University of California, Berkeley told The New York Times. "All I can say fairly definitively is that the [Associated Press]-released recording is of a cricket, and we think we know what species it is."
Stubbs, along with co-author Fernando Montealegre-Z of the University of Lincoln in England, recently submitted a paper outlining both their analysis of the strange recordings and their conclusions that it belongs to the incessant mating call of the Indies short-tailed cricket.
Normalized amplitude spectrum of potential sound sources compared to the recording published by the Associated Press. (Photo: Alexander Stubbs/Fernando Montealegre-Z)
"As shown here, the calling song of the Indies short-tailed cricket (Anurogryllus celerinictus) matches, in nuanced detail, the AP recording in duration, pulse repetition rate, power spectrum, pulse rate stability, and oscillations per pulse," they write. "The AP recording also exhibits frequency decay in individual pulses, a distinct acoustic signature of cricket sound production."
While the scientists initially found small differences in comparing the acoustic signatures, they soon fixed the issue by recording the sound of the short-tailed cricket in the same way the diplomats would have heard it: from within a house. A near-perfect match of the crickets' piercing trill, a mind-numbing song you can play for yourself here, was then achieved.
"They're incredibly loud," Stubbs told the Times. "You can hear them from inside a diesel truck going forty miles an hour on the highway."
While they believe they've confirmed the source of the recording published by the Associated Press, the scientists nonetheless don't have answers for why the sounds triggered such harmful symptoms in the diplomats.
"Although the causes of the health problems reported by embassy personnel are beyond the scope of this paper, our findings highlight the need for more rigorous research into the source of these ailments, including the potential psychogenic effects, as well as possible physiological explanations unrelated to sonic attacks," they conclude.