There once was a magic golden turtle that lived in Hanoi's most enchanted lake. A creature so powerful, it snatched a divine sword from a warrior king and returned it to the gods of the depths nearly six centuries ago.
That tale has long been a favorite among young and old Vietnamese living in the capital city, but folklorists may soon have to rewrite the story to include a very sad ending.
That's because in real life, the last giant soft-shell turtle living in Hoan Kiem Lake will probably die alone, and at least one biologist says the species will then be extinct.
The elusive creature -- with a shell as big as a desk -- occasionally pokes its wrinkled head out of the murky waters of the downtown lake to take a breath, but few Vietnamese are lucky enough to glimpse it. And certainly no one knows its age.
Scientists say it probably is the most endangered freshwater turtle species in the world.
"This species is a huge, huge animal that's incredibly endangered and it really needs help," said Anders Rhodin, co-chairman of the World Conservation Union's Tortoise and Freshwater Turtle Specialist Group. "I don't think anyone is willing to try to capture that animal in Hoan Kiem Lake. I think it is thought to be sacred."
Conservationists are determined, however, not to let the legendary species die out. This month, researchers from Hanoi National University and the U.S.-based Wildlife Conservation Society plan to scout lakes in Thanh Hoa province, 100 miles south of Hanoi, where other giant turtles have been sighted, but never confirmed.
"We're going to the province to see whether there's any truth to this," said Douglas Hendrie, the society's Asia regional turtle conservation coordinator who has worked in Vietnam since 1996. "The species is very, very, very important to Vietnam culturally and therefore of high priority when it comes to conservation."
Legend has it that in the mid-15th century, King Le Loi defeated Chinese invaders with a magic sword given to him by the gods. After the victory, the king was said to be boating on the lake when a giant golden turtle rose to the surface and grabbed the sword in its mouth before plunging deep into the water to return it to its divine owners.
The lake was later renamed "Ho Hoan Kiem," which means "Lake of the Returned Sword," and the tale became an important part of Vietnamese culture that continues to be taught in school and performed at popular water puppetry shows.
But just like the Loch Ness Monster or the Tasmanian Tiger, no mythical creature comes without controversy. Vietnamese biologist Ha Dinh Duc, who has studied the lone turtle since 1991, reported in 2000 that it was a new species and named it Rafeteus leloii after the king.
Other scientists dispute his conclusion, saying at least five other turtles of the same species, Rafeteus swinhoei, have been found in zoos and a monastery in neighboring China.
But Duc, who vows to study the turtle for the rest of his life, said no one has spent more time researching and viewing it than he has.
"There's no other types of turtle like this in other countries," Duc said. "Their assessment is totally wrong."
As he slid his wire glasses up his nose and rifled furiously through years of yellowed papers and stacks of color photos, he spoke about the turtle like a child.
It weighs about 440 pounds and its massive shell stretches 6 feet long and 4 feet wide. Its gender remains a secret along with its age because Duc says only he has been lucky enough to view it completely out of the water a few times as it rested on an island in the middle of the small, shallow lake.
Hendrie said the turtle could probably live up to 100 years, but Duc believes that it's conceivable for the animal to be old enough for Le Loi himself to have released it into the lake, which was once part of the Red River.
The World Conservation Union ranks the turtle as critically endangered, the most threatened category, saying it is "perilously close to extinction" and "currently probably the most endangered freshwater turtle in the world."
Its precarious circumstances mirror those of many turtle species, especially in Asia. The organization says 74% of the continent's 90 freshwater turtle and tortoise species are listed as threatened because of continuing demand for food and traditional medicine.
Hendrie and Rhodin said they're optimistic about finding other giant soft-shell turtles in the wild or placing the ones in China together in captivity to try to save the species from extinction. Turtles remain fertile until death, so it's possible for even very old animals to mate, but they said more research is necessary before steps can be taken.
However, the prospects for the Hoan Kiem turtle, as it is known, look bleak. Duc said three others like it emerged from the lake in the 1960s, but all of them have died and all of the scientists agree that only one remains. One huge stuffed specimen is displayed in a small temple on an island in the lake, but not even Duc is bold enough to disturb the revered remaining creature that will undoubtedly have its own legend centuries from now.
"No one is allowed to touch this turtle," Duc said, sitting by the water. "If something went wrong, who would be responsible? It would be a big deal that would impact the soul of a nation."