Sweden was at the forefront of keeping an eye on the Soviet Union during the Cold War. And even after the collapse of the USSR, the Swedish navy suspected the Russians of running covert submarines into their waters. In 1994, sonic recordings that sounded suspiciously like submarine activity caused a diplomatic row between Sweden and Russia that went on for ten years.
This diplomatic conflict raged on until 2004, when scientists made a vital diplomatic discovery: Herrings fart. Sent out to investigate the sound, researchers Magnus Wahlberg and Hakan Westerberg discovered that the hissing came from bubbles filled with gas, which herrings secrete through their anuses to covertly communicate with one another. (Same spycraft, different species.)
The researchers referred to the communications system as "fast repetitive ticks," or FRTs, and these FRTs just happened to sound exactly like the whoosh of a submarine. The discovery cleared the Russians of any wrongdoing, set the Swedish navy's mind at ease, and won Wahlberg and Westerberg an Ig Nobel prize to boot. Maybe diplomats should try blaming things on fish more often.
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(Image credit: Yury Dolgorukiy)