You may have heard the expression, “Snatching victory from the jaws of defeat.” But what if you could snatch victory from defeat’s throat?

This twist on a familiar phrase is inspired by the Japanese eel. A recent study found that when a predator swallows these wriggly creatures, the eels don’t go down without a fight. Instead, they poke their tails up the predator’s esophagus—and slither right out of its gills.

Here’s how it works. The predator in question, called the dark sleeper fish, gulps down its meal in one bite, swallowing the eel and surrounding water all at once. Plunging headfirst into the stomach, the eel, if it’s lucky, will keep its tail in the dark sleeper’s esophagus. Otherwise, it swims around the digestive track, seeking an exit. Even if it can find the esophagus, the eel must then successfully poke its tail through the gills, back out, and yank its head free. Talk about “to turn tail and run!”

You’d think such a great escape would leave the sleeper fish hungry. The eels, though, don’t always make it out alive. Researchers used an X-ray video system to watch 32 eels in a tank get eaten—only 9 of them successfully wriggled free. And once ingested, the clock is ticking: the highly acidic stomach can kill an eel in under four minutes.

The lucky runaways emerged with only some minor scrapes, and the dark sleeper fish was unharmed from their prey’s vanishing act. But in the world of eat or be eaten, the eels’ escape gives new meaning to losing your lunch!

A special thanks goes to Yuha Hasegawa and Yuuki Kawabata, Nagasaki University, for reviewing today's episode.

Learn More

• Scientists Discover Two New Species Of Eel
• Zap! How electric eels create their shocks
• Soft, Stretchy Batteries

Sources                                  

Hasegawa, Yuha, Kazuki Mine, Katsuya Hirasaka, Kazuki Yokouchi, and Yuuki Kawabata. “How Japanese eels escape from the stomach of a predatory fish.” Current Biology, vol. 34, no. 17, September 9, 2024. https://www.cell.com/current-biology/fulltext/S0960-9822(24)00926-6.

Davis, Nicola. “Japanese eels can escape predators’ stomach through their gills, finds study.” The Guardian, September 9, 2024. https://www.theguardian.com/environment/article/2024/sep/09/japanese-eels-escape-predator-stomach-gills-study.

Roth, Annie. “The Terrifying Way That Eels Escape a Hungry Fish’s Stomach.” The New York Times, September 9, 2024. https://www.nytimes.com/2024/09/09/science/eels-escape-fish-stomach.html.