In late 2016, American diplomats living in Cuba started hearing
a strange noise in their homes. It was high-pitched, deafening, and persistent—and no one could work out where it was coming from.
In the following years, the mystery ballooned into an international incident. Many of the diplomats experienced dizziness, insomnia, hearing loss, and other troubling symptoms. A team from the University of Pennsylvania examined 21 affected people and
concluded that they had “sustained injury to widespread brain networks,” based on evidence that other neurologists said was “
almost unbelievably flimsy.” Donald Trump, without evidence,
accused Cuba of being responsible. Various parties argued that the strange noise was the result of a
sonic weapon, a
microwave attack, or
malfunctioning eavesdropping equipment.
But when the biologist
Alexander Stubbs heard a recording, uploaded by the Associated Press, he heard not mechanical bugs, but biological ones. He realized that the noise sounded like the insects he used to hear while doing fieldwork in the Caribbean.
Together with Fernando Montealegre-Z, an expert on entomological acoustics, Stubbs scoured an
online database of insect recordings. As first
reported by Carl Zimmer in
The New York Times, they found that one species—
the Indies short-tailed cricket—makes a call that’s indistinguishable from the enigmatic Cuban recording. The duo have
written a paper that describes their findings and are set to submit it to a journal for formal peer review.
After analyzing similar recordings, the Cuban government had also pointed its finger at crickets. But they
blamed the wrong species—one whose song sounds very different, even to untrained ears. By contrast, the song of the Indies short-tailed cricket matches the Cuban noise in several telltale ways. Both are loudest at a frequency of 7 kilohertz, roughly an octave beyond the highest notes on a piano. Both consist of pulses that repeat 180 times a second. In both, each pulse consists of 30 oscillations, which become slightly lower in pitch as they die away.
Only one thing didn’t match: The pulses in the AP recording were more erratic and variable than those of most insects. But that, Stubbs thinks, is because the cricket’s call was probably echoing off the surfaces of an indoor space, creating several sound streams that interfered with one another. When he played and recorded the cricket’s call indoors, the result matched the Cuban noise even more closely.
Cricket behavior could also help explain another mysterious detail of the Cuban incidents: Several diplomats claimed that the sound abruptly stopped when they entered a room
or moved around. That’s “consistent with an insect stopping a call when threatened,” Stubbs and Montealegre-Z write.
