Glassfrogs make themselves transparent while they rest by taking red blood cells from circulation and concealing them in their livers. Now, a U.S. National Science Foundation-supported team of biologists and biomedical engineers has shown how these frogs become see-through in research appearing in the journal Science .
It's easy to miss a glassfrog in its natural environment. The northern glassfrog, Hyalinobatrachium fleischmanni, measures no more than a few centimeters and is most active at night, when its green skin helps it blend in with surrounding leaves and foliage. But these amphibians become true masters of camouflage during the day when they're asleep.
"When glassfrogs are resting, their muscles and skin become transparent, and their bones, eyes and internal organs are all that's visible," said Carlos Taboada, co-first author of the paper. "These frogs sleep on the bottoms of large leaves, and when they're transparent, they can perfectly match the colors of the vegetation."