In a study published on Monday in the journal Current Biology, scientists filmed juvenile Japanese eels staging Houdiniesque feats of escape from inside a predatory fish. After being swallowed and deposited into the fish’s stomach, the young eels swam up the hunter’s esophagus and escaped through an opening in its gills, much to the fish’s displeasure.
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[They] escape by wriggling their way, tail first, out of the digestive tract, up the esophagus and out the gills.
https://archive.ph/VqezR
The NYT uses SEO garbage in the title...
The Terrifying Way That Eels Escape a Hungry Fish’s Stomach
There’s a species of beetle that’s evolved a shell that can withstand stomach acids for several hours. They get eaten by frogs, they just crawl their way out to the other end.