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The Japanese eel successfully crawled back out of the predatory fish’s stomach, then escaped through its gill slits.
Japanese eel successfully escapes from the stomach of a predatory fish (Photo: Getty).
Few insects or mollusks can survive being swallowed by a fish. However, the Japanese eel (scientific name: Anguilla japonica) has been very successful in doing so.
Using X-ray video, scientists from Nagasaki University, Japan, recorded the entire event, as well as the eel’s escape strategy.
Remarkably, active escape from the digestive tract of predators seems to have become a habit of this eel species.
Specifically, out of 32 eels participating in the experiment, 13 individuals found a way to escape from the fish’s stomach and regain freedom.
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Video: How eels get out of fish’s stomach after being swallowed (Source: Nagasaki University).
To do this, they writhe and crawl backwards, aiming to get back into the fish’s esophagus. However, the eels do not escape directly from the predator’s mouth. Instead, they find the connecting piece between the gill slits and emerge from there.
This increases the survival rate of the eels, as they are not swallowed back by the fish.
The discovery provides new insights into eels’ muscular strength and ability to withstand highly acidic, anaerobic environments, the researchers said.
In addition, the eel’s long and slippery shape are also necessary factors for them to quickly exit the digestive tract before being absorbed.
On average, the maximum time it takes for each eel to escape from the fish’s body is about 4 minutes, before they die in the predator’s digestive environment.