TRUE STORY

Cold War paranoia had plenty of real causes. This is the story of one that came from the other end of a fish.

Whiskey on the Rocks

On October 27, 1981, Sweden woke up to an alarming discovery. A Soviet submarine, U 137, had run aground in the archipelago outside Karlskrona, close to one of the country’s most important naval bases. The Soviets blamed navigation errors. The Swedes were not convinced, and many suspected the boat was carrying nuclear weapons.

The submarine sat stuck on the rocks for 11 days. Because it was a Soviet “Whiskey-class” sub, the incident became known as “Whiskey on the Rocks.” Eventually a Swedish tug escorted it back to international waters. But the damage was done. Neutral Sweden now had proof that Soviet subs were creeping around its coastline, and it was determined to catch the next one.

Strange Noises in the Deep

Over the following years, the Swedish navy’s underwater microphones kept picking up odd sounds near its coast, which listeners compared to bacon frying. To navy ears, the meaning seemed obvious: foreign submarines, probably miniature ones, slipping through Swedish waters.

The hunts were serious. In one search, submarines, surface ships and helicopters reportedly combed the water for about a month and found nothing but the occasional bubbles. The sounds kept coming. The subs never surfaced. To the people tracking them, that only made the intruders seem more cunning.

The Prime Minister Puts It in Writing

By 1994, the Soviet Union was gone, but the mystery noises weren’t. Swedish Prime Minister Carl Bildt took the matter to the top and wrote to Russian President Boris Yeltsin demanding an explanation for the intrusions.

Yeltsin’s reply amounted to a polite shrug. Russia, he indicated, knew nothing about it.

That denial was more accurate than anyone in Stockholm realized at the time.

Enter the Scientists

In the mid-1990s (1996, by one account), the navy brought civilian researchers into its secret acoustic facility for the first time. Among them were biologists Magnus Wahlberg and Håkan Westerberg. They listened to the mystery recordings and set out to find what was making the noise. The answer came from somewhere nobody had thought to look.

Herring have a swim bladder connected to their digestive tract, which lets them push gas out through a duct near their rear end. When they do it, they make a burst of tiny ticking pulses. Recorded on sensitive military equipment, a big school of herring letting rip sounds remarkably like something mechanical moving through the dark. And Baltic herring schools can stretch across several square kilometres.

The “submarines” were fish, breaking wind.

Meanwhile, a separate team of scientists, Ben Wilson, Lawrence Dill and Robert Batty, had independently discovered the same thing in Pacific and Atlantic herring. They named the sound a “fast repetitive tick,” or FRT. (Draw your own conclusions about the acronym.) They found that the herring mostly made the noise at night and suggested it might help schools stay together in the dark.

Glory, at Last

In 2004, all five researchers shared the Ig Nobel Prize in Biology, the award for research that first makes people laugh and then makes them think. The official citation honoured them:

“For showing that herrings apparently communicate by farting.” — Ig Nobel citation, via Improbable Research

The awards committee didn’t even know about the submarine part of the story. Wahlberg and Westerberg finally told that side publicly in 2012, at an Ig Nobel event in Stockholm, using a dead herring to demonstrate exactly how the mechanism works.

The Last Word

Years of tension, naval hunts, and a letter from one head of government to another, all prompted in part by fish passing gas.

Sweden spent years trying to catch a Soviet intruder, and at least some of the time the “enemy” was already in the Baltic, chatting with its friends.

Sources

• ASD Europe: Baltic herring nearly escalated Cold War tensions
• Improbable Research: The Swedish prime minister, a Soviet submarine and farting herring
• Improbable Research: A vivid telling of the herring farts / Soviet sub history
• Sveriges Radio: When the Cold War washed up on Sweden’s shores
• Nature News: 2004 Ig Nobel coverage
• Practical Fishkeeping: Farting fish research wins Ig Nobel