Image courtesy of Hasegawa et al./Current Biology
Joel Kontinen
X-ray videos of Japanese eels swallowed whole by dark
sleeper fish have revealed how the eels can make a daring escape from being
digested.
Japanese eels try to wriggle back out of the stomachs of fish that have swallowed them whole – and now we know how they sometimes succeed.
A few years ago, Yuha Hasegawa at Nagasaki University
in Japan noticed that Japanese eels (Anguilla japonica) that had been swallowed
by fish were somehow reappearing in tanks. Further investigation revealed that the eels were
escaping through the gills of fish, with 28 out of 54 eels that had been
observed being swallowed whole managing to escape – but exactly how they
managed this feat was unclear.
Now, Hasegawa and colleagues have managed to film the
process by injecting eels with a contrast agent that makes them visible on
X-rays. Of 32 eels that were filmed being swallowed whole by dark sleeper fish
(Odontobutis obscura), 12 managed to go back up the gullet far enough to bend
their tail around and get it out of a gill slit. Of these 12, nine escaped.
In some cases, the tails of the eels weren’t fully in
the fish’s stomach when they starting moving backwards up the gullet, b in
others the entire body was in the stomach, with the eels circling around as if
looking for a way out. Five out of 11 eels that were fully in the stomach
managed to put their tail into the gullet entrance and back up towards the
gills.
The eels strategy is through the intelligent design
that works in them, This happened after
the events recorded in Genesis 3 on the Fall of man.
Source:
Michael Le Page 2024. Watch eels escape from the stomachs of fish after being swallowed | New Scientist 9 September.
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