For humans, walking on the surface of the water is the stuff of miracles. For animals, it’s a little more commonplace. An article at Live Science from 2010 notes that around 1,200 species have this ability — which, for the most part, can be found in smaller animals like water striders and spiders. That’s not all that surprising. After all, navigating on the surface of the water without falling in is a delicate operation, and something that a more minute creature would be able to accomplish more easily than something bigger.
But what about walking on the surface of the water upside down? This might seem impossible, the stuff of thought experiments and psychedelic paintings. But as it turns out, it’s not — and one researcher at Australia’s University of Newcastle has discovered evidence that this is possible. Even better, he’s documented the phenomenon on video.
At The Guardian, Donna Lu has more information on the discovery. PhD student John Gould was in the Watagan Mountains researching frogs when he noticed something strange in a nearby body of water. Specifically, he saw a beetle walking across the surface of the water, but upside down and underwater.
“The most interesting thing is that it’s able to rest on the underside of the water’s surface as well as walk,” Gould told The Guardian.
Gould went on to co-author a paper on the subject for the journal Ethnology. While observing the beetle, Gould noticed air trapped along its abdomen. In the paper, he suggests that “the air bubbles located on the abdomen and/or legs may be providing the upward force necessary for the beetle to be pushed against the underside of the water’s surface.”
It’s a fascinating discovery, and one that might expand our knowledge of how different species inhabit the world. It doesn’t hurt that watching something walk upside down while underwater is oddly mesmerizing as well.