The bizarre turtle that urinates through its mouth... and is a delicacy in Chinese restaurants
Most usually encountered at upmarket restaurants in China, where they are considered a delica...
Most usually encountered at upmarket restaurants in China, where they are considered a delicacy, these unusual reptiles are the only animals known to urinate through their mouths.
Now scientists believe that this apparently unique ability helped the animals adapt to survive in swamps and marshes where the water is often brackish - that is, slightly salty. Scientists in the 19th Century discovered that the linings of the mouths of soft-shelled turtles are covered with tiny, finger-shaped protrusions.
Subsequent research revealed that these allow the turtles to breathe underwater by increasing the surface area of the mouth where oxygen and carbon dioxide can be exchanged.
But Alex Yuen Kwong Ip of the National University of Singapore believes that these characteristics evolved for one reason only: to help the turtles urinate through their mouths more easily.
Together with Shit Fun Chew of Singapore's Nanyang Technological University, Professor Ip kept four turtles in tanks of water for six days, New Scientist reported.
The researchers found that, incredibly, only 6 per cent of the turtle's urea came out of the cloaca, with the rest mysteriously turning up in the tank's water.
Professor Ip also restrained the turtles on land. He found that when he placed a bucket of water in front of them the creatures plunged their heads in for between 20 and 100 minutes.
Observing more closely, he watched as they held some water in their mouths for a while then spat it out, increasing the concentration of the urea in the water.