We’ve written about some bizarre animals in the past, but just when you think nothing can come as a surprise… well, meet the Chinese soft-shelled turtle, an animal that has an unique ability, never before encountered in the animal kingdom – it can urinate through its mouth.
This is definitely not your typical turtle, even its appearance warns that there’s something really special about it; just look at it – it has a pig snout, on top of a fish’s head, and eyes that I can’t really trace right now to something familiar. Even as an embryo, this turtle is one special animal, as it moves towards the warmest part of the egg, without any developed limbs. Locals mind little of the fact that it urinates through its mouth, and if the turtle can’t be found through South Asian rain forests, rest assured it’s on the menu of most restaurants in the area.
The turtle’s linings in its mouth are covered with tiny protrusions, which allow it to breath underwater for long periods of time by increasing the surface area over which oxygen and carbon dioxide can be exchanged. Some researchers believe that this treat was evolved simply to allow the turtles to urinate under water, and that’s not to say that the turtle doesn’t have any other urea exit options. It still has a cloaca, where urine would normally exit the body.
Scientists weren’t sure about the turtle’s unique ability until it was put to the test. Alex Yuen Kwong Ip, along with colleague Shit Fun Chew, of the National University of Singapore introduced four turtles in water tanks for six days. A tube was attached to each turtle’s cloaca for unique collection. The scientists found that only about 6% of the total urea came out the cloaca, the rest came out through its mouth directly in the water tank. Alright, maybe the soft-shelled turtle is simply evolutionary constrained to urinate through its mouth when under water, considering the same exit or entrance, whichever you prefer, is used for breathing as well. So the researchers tried a land test. When a bucket of water was put in front of the turtles, on land, they plunged their heads in for between 20 and 100 minutes. During this time they held water in their mouths for a while, then simply spitted out – urea concentration evidently rose in the buckets’ water. At this point, as I’m writing this, I can’t help but reminisce of what’s maybe the most twisted and vile South Park episode.
“I know of no other animals that can excrete urea through the mouth,” says Ip.
Neither do I, but apparently this isn’t a simple cruel joke played by nature. Analysis has shown that urinating through an oral route is 15 to 50 times more faster than going past the kidney. The researchers also believe oral urination helped turtles colonise brackish waters. To excrete urea through their cloaca via their kidneys, the turtles would need to drink a lot of water to flush it through, so oral urination came in handy.
ZME readers, what other bizarre animals do you know?
The findings on the Chinese soft-shelled turtle were described in the Journal of Experimental Biology.
via New Scientist
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