Green To the Bone (IMAGE) Duke University Caption The glass frog Espadarana has translucent skin and green insides, thanks to an evolutionary adaptation that turned a toxic byproduct of blood breakdown into a lovely green pigment. Even its bones are green. Credit Santiago R. Ron Usage Restrictions Please credit: Santiago R. Ron License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.