Scientists have discovered how eels manage to survive being eaten by predators. A study entitled “How Japanese eels escape from the stomach of a predatory fish” placed a number of eels in water with common predators and used X-rays to examine what happens after the predator swallows its prey. In an impressive display, the eel manages to escape through the gills of its would-be killer, even after being swallowed whole.
Yuha Hasegawa of Nagasaki University, who conducted the research, said it was previously believed that the eel escaped through the predator’s mouth, but the findings reveal that the slippery creature winds its way out of a fish’s stomach and makes a beeline toward its gills to escape.
The fish used in the study were the Odontobutis obscura, which can swallow Anguilla japonica (Japanese eels) whole. Extraordinary footage shows the eel inside the fish’s stomach, swimming in circles and apparently searching for the exit until it makes its getaway. Kory Evans of Rice University in Houston said that many fish have a second set of jaws which usually finish off their prey, “so the idea of anything escaping those jaws not only intact but alive is pretty impressive.”
According to analogous research, other creatures perform similar remarkable feats of survival, with some escaping through the back end of their predator. Species of land snail, for instance, have few escape options due to their slow movement, so rely on withdrawal into their shell and an offensive taste and smell. However, if those fail, scientists have found that the animal is not only able to survive being eaten but being digested.
In a 2012 study, researchers on Hahajima Island in the western Pacific fed adult snails measuring around 2.5 mm in height to several birds, including the Japanese white-eye bulbul and the brown-eared bulbul. When the birds had eaten their fill, researchers waited for nature to take its course. After the bulbuls eventually paid a visit to the restroom, scientists were surprised to find that 15% of the snails had survived the entire digestive process and passed through the gut alive.
