Glassfrogs conceal blood in their liver to maintain transparency.

TitleGlassfrogs conceal blood in their liver to maintain transparency.
Publication TypeJournal Article
Year of Publication2022
AuthorsC Taboada, J Delia, M Chen, C Ma, X Peng, X Zhu, L Jiang, T Vu, Q Zhou, J Yao, L O'Connell, and S Johnsen
JournalScience (New York, N.Y.)
Start Page1315
Pagination1315 - 1320
Date Published12/2022

Transparency in animals is a complex form of camouflage involving mechanisms that reduce light scattering and absorption throughout the organism. In vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells (RBCs) that strongly attenuate light. Here, we document how glassfrogs overcome this challenge by concealing these cells from view. Using photoacoustic imaging to track RBCs in vivo, we show that resting glassfrogs increase transparency two- to threefold by removing ~89% of their RBCs from circulation and packing them within their liver. Vertebrate transparency thus requires both see-through tissues and active mechanisms that "clear" respiratory pigments from these tissues. Furthermore, glassfrogs' ability to regulate the location, density, and packing of RBCs without clotting offers insight in metabolic, hemodynamic, and blood-clot research.

Short TitleScience (New York, N.Y.)