These frogs can turn almost invisible by hiding their red blood cells. Here’s how they do it.
A group of glassfrogs sleeping together upside down on a leaf, showing their camouflage.
Jesse Delia says it happened in Panama. A few years back, he was finishing up his field work — a research project examining the parental behavior of a type of glassfrog. He brought a handful of these transparent, half dollar-sized frogs to the lab for a photo shoot."I wanted to get some photos of a pretty glassfrog belly," Delia tells NPR. He placed them in a Petri dish and saw each frog's circulatory system through its translucent skin —"red with red blood cells.
It was as if the arteries and veins had just melted away."I thought it was crazy," recalls Delia, now a biologist at the American Museum of Natural History in New York. He took a video of the glassfrog's pumping heart and sent it to his longtime collaborator, Carlos Taboada, a biologist at Duke University.
"It was colorless," Taboada says. Not even the telltale red streak of a vessel in the frog's belly was visible."It was insane. I had never seen anything like that."