Water beetles escape death by crawling out of their predators’ butts

Water beetles eaten by dark-spotted frogs escape through the amphibians’ digestive tract and use the back door, according to a report in Current Biology.

The study, published Monday, claims water beetles that successfully escape through the rear exit have to do so quickly, as frogs’ digestive juices will dissolve prey that sticks around. Japanese researchers found that 90% of the beetles observed were passed within six hours and the bugs were still alive when they emerged from the excrement of the frogs that ate them.

But when researchers waxed the legs of water beetles so they couldn’t run, then fed them to frogs, the beetles all died and were passed more than a day later.

“This study is the first to document active prey escape from the vent of a predator and to show that prey may promote predator defecation to hasten escape from inside the predator’s body,” the report claimed.