Once upon a time, a water beetle was swallowed by a frog. The intrepid insect survived the journey through the frog's mouth, esophagus, stomach, and intestines, then found itself at what scientists call the frog's "vent"—in other words, its anus. So close to freedom. The insect twitched its hind legs, maybe out of fear, maybe out of genius. The movement made the frog poop, and the water beetle escaped through the vent into freedom. Now that behavior is seemingly ingrained into the beetles' DNA, because the same crazy journey unfolds time and time again, reports Live Science. This was discovered by researcher Shinji Sugiura of Japan's Kobe University, who set up a camera to try to figure out how the beetles kept re-emerging after being swallowed. He figured they did so via the frog's mouth, but it turned out to be the other end.
"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," Sugiura writes in Current Biology. To test the latter part of the theory, he used wax to stick the hind legs of some beetles together. Unable to stimulate the frog's need to poop, they never re-emerged. The beetle likely survives the journey because its "streamlined, but sturdy, exoskeleton" protects it from the frog's digestive juices, per a post at ScienceNews. Plus, the beetle is able to breathe underwater thanks to air pockets under its wings, so it can survive an extended period in the frog's innards. Once swallowed, most of the beetles are back out in a matter of hours. And, yes, you can watch the great escape for yourself here. (Read more frogs stories.)