Glassfrogs conceal blood in their liver to maintain transparency
Transparency provides a form of camouflage that is particularly useful
for increasing crypsis in motionless animals. Many taxa have evolved
transparency, but it is particularly challenging for vertebrates because
red blood cells attenuate light. Taboada et al. found that glass
frogs are able to maintain a high level of transparency because a large
proportion of their red blood cells are “hidden” in the liver (see the
Perspective by Cruz and White). This strategy allows the frogs to attain
transparency when they are the most vulnerable. Understanding this
liver-packing process may inform our understanding of hemodynamics more
broadly.