Yuen K. Ip knew something funky was going on inside the mouths of Chinese soft-shelled turtles. When they were on dry land, they dunked their heads in puddles and gargled. “Why would they do that?” asks Ip, a physiologist at the National University of Singapore. It turns out they were simply peeing. From their mouths.
Mouth-peeing is more than just a neat trick—it’s essential for maintaining these turtles’ deviant lifestyles. Unlike other freshwater turtles, these guys venture into brackish water for days at a time. In this challenging environment, their bodies break down protein and produce toxic ammonia, packaging it as urea.
The load is so great that they cannot just drink water and flush it out because their kidneys would be overwhelmed by the salts. Instead, these turtles have molecular pumps in their mouths that help move the urea out.
Ip thinks his research could help humans with kidney failure, either by creating a more efficient dialysis machine or through gene therapy to enable humans to mimic the turtle and eliminate urea via the mouth. It may just work. “What we are doing is learning from nature,” he says.
