Watch an eel climb up its predator's digestive tract and wriggle to freedom through its gills

An xray showing an eel inside the digestive tract of a dark sleeper fish.

Japanese eels have found an ingenious way to escape a fish's stomach after being swallowed — backing up the digestive tract then squeezing themselves out of the predator's gills.

In a scientific first, researchers in Japan have used X-ray videography to capture the behavior of live prey inside its predator's digestive tract.