A kind of transparent frog achieves near invisibility by hiding its red blood cells during the day, scientists found. "I had never seen anything like that," researcher Carlos Taboada says.

When glassfrogs sleep, they turn their bodies transparent in order to evade predators. Scientists have now discovered that they do so by moving their red blood cells into their liver – and the ...

Glassfrogs can render themselves nearly invisible while they sleep with a unique trick; they pack nearly 90% of their red blood into one of their organs.