Scientists reporting in the Journal of the American Chemical Society examined solid urine from more than 20 reptile species and found tiny uric‑acid spheres that package waste while conserving water. The study, highlighted by the American Chemical Society and ScienceDaily, also suggests uric acid helps convert toxic ammonia into a less harmful solid, a mechanism that could guide future strategies against gout and kidney stones.
Many reptiles and birds excrete some nitrogenous waste as solid "urates" rather than solely as liquid urine, an adaptation thought to conserve water. These solids are expelled through the cloaca and differ from human waste elimination, which primarily flushes urea, uric acid and ammonia in liquid form, according to the American Chemical Society (ACS).
In a new analysis led by Jennifer A. Swift of Georgetown University, researchers studied urates from more than 20 reptile species, including ball pythons, Angolan pythons and Madagascan tree boas. Using electron microscopy and X‑ray techniques, the team reported that the urates are made of textured microspheres about 1 to 10 micrometers wide, themselves built from nanocrystals of uric acid monohydrate.
The work aims to understand how reptiles safely manage crystalline waste that in humans can be harmful. Excess uric acid can crystallize in joints, causing gout, or form stones in the urinary tract. “This research was really inspired by a desire to understand the ways reptiles are able to excrete this material safely, in the hopes it might inspire new approaches to disease prevention and treatment,” Swift said in ACS press materials.
Beyond structure, the researchers report that uric acid appears to help convert ammonia—a toxic byproduct—into a less toxic solid form. While the authors and ACS emphasize that further study is needed, they note the chemistry behind these reptile crystals could eventually inform how clinicians think about uric acid–related disorders.
The study, “Uric Acid Monohydrate Nanocrystals: An Adaptable Platform for Nitrogen and Salt Management in Reptiles,” lists authors Alyssa M. Thornton, Timothy G. Fawcett, Amanda K. Rutledge, Gordon W. Schuett and Jennifer A. Swift. It was published online Oct. 22, 2025, in the Journal of the American Chemical Society (DOI: 10.1021/jacs.5c10139). Funding acknowledgments include the National Science Foundation, Georgetown University, the International Centre for Diffraction Data and the Chiricahua Desert Museum.
