Transparency is a common form of camouflage among animals that live in water, but it’s rare on land

Found in American tropics, Glass frogs are nocturnal amphibians who sleep upside down on translucent leaves that match the colour of their backs — a common camouflage tactic

Their bellies have translucent skin and muscle that allows their bones and organs to be visible, giving the glass frog its common name

Ice fish & larval eels achieve transparency by not producing hemoglobin & red blood cells. But glass frogs use an alternative strategy, according to the findings of the new study

The study conducted by researchers at Duke University & the American Museum of Natural History used a technique called photoacoustic imaging, which uses light to induce sound-wave propagation from red blood cells.

The study found resting glass frogs increase transparency by removing nearly 90% of their red blood cells from circulation & packing them within their liver, which contains reflective guanine crystals

In most vertebrates, aggregating red blood cells can lead to potentially dangerous blood clots in veins and arteries. But glass frogs don’t experience clotting

The study raises a set of significant questions for biological & medical researchers & may open up new directions in the breakdown of blood clots which frogs manage to avoid on a regular basis