[Photo] The Swinhoe's soft-shell turtle was thought to be extinct in nature. (Credit: Image courtesy of Cleveland Metroparks Zoo)

ScienceDaily (Apr. 16, 2008) — "Swinhoe's soft-shell turtle" was thought to be extinct in nature. Cleveland Metroparks Zoo has just announced the discovery of a critically endangered turtle in northern Vietnam that previously was thought to be extinct in the wild. Experts from the Zoo's Asian Turtle Program confirmed that they have identified the only known living specimen of a Swinhoe's soft-shell turtle (Rafetus swinhoei) in nature.

After three years of searching lakes and wetlands along the Red River in northern Vietnam, researchers sponsored by Cleveland Metroparks Zoo and the Cleveland Zoological Society, turned their focus to a lake just west of Hanoi, where local residents claimed to have occasionally seen the gigantic soft-shell turtle. Field biologist Nguyen Xuan Thuan, with Education for Nature in Vietnam, found and photographed the turtle as it basked on the lake's surface, allowing scientists to confirm the animal was the extremely rare Swinhoe's turtle.

This is an incredibly important discovery because the Swinhoe's turtle is one of the most critically endangered species of turtle in the world," said Doug Hendrie, the Vietnam-based coordinator of Cleveland Metroparks Zoo's Asian Turtle Program. "This species has legendary status among the people of Vietnam, so this is perhaps an opportunity for the legend to live on."

Other than the turtle discovered by Cleveland Metroparks Zoo's Asian Turtle Program, only three of the giant turtles are known to remain. Two of them are at zoos in China, and one is in the Hoan Kiem Lake in Hanoi. The Swinhoe's soft-shell turtle is considered by many in Vietnam to be a national treasure.

According to folklore, the rare turtle has emerged at key points in Vietnam's history. The legend says that in the 15th century, the giant turtle rose from Hoan Kiem Lake to reclaim a magical sword that was given to Emperor Le Loi to expel the Chinese army from Vietnam. Some people believe that the single, large soft-shell turtle that occupies the lake today is the very same turtle that retrieved the sword from the Emperor and returned it to God.

Hanoi residents often line the banks of Hoan Kiem Lake in hopes of spotting the legendary turtle, which some believe brings good fortune to those who see it.

"This is one of those mythical species that people always talked about but no one ever saw, so it's hugely significant that we found this lone turtle in the wild," said Geoff Hall, General Curator of Cleveland Metroparks Zoo. "It gives us some hope for a species that truly is on the verge of extinction."

The demise of this revered species is largely due to hunters who captured and killed them for food or to make traditional medicine from their bones. Loss of nesting habitats along major rivers and pollution also are to blame. And while the recent discovery of another specimen of the Swinhoe's turtle is promising, the future of the species remains uncertain.

"Our hopes are set on finding other turtles that have somehow been overlooked by hunters or were preserved in lakes and wetlands along the Red River," Hendrie said. "However, without evidence of reproduction, the future of the legendary Hoan Kiem turtle and its three surviving cohorts looks bleak."

Efforts are underway to unite the male and female soft-shell turtles at the two separate Chinese zoos in hopes they may reproduce and ensure another generation of the species.

The largest freshwater turtle in the world, the Swinhoe's soft-shell turtle also is referred to as the Shanghai soft-shell turtle or the Yangtze soft-shell turtle. The giant turtles can weigh up to 300 pounds and measure up to 3_ feet with some living to more than 100 years old. The species historically could be found in the Red River basin of northern Vietnam, extending north into southern China and along the Yangtze River in eastern China.

Before announcing their big discovery, the team of Zoo-supported researchers notified senior government officials and took measures to protect the turtle in its natural habitat. The Swinhoe's turtle remains in the lake where it was found.

The Asian Turtle Program is a special conservation program of Cleveland Metroparks Zoo and the Cleveland Zoological Society, with all work in Vietnam being carried out in partnership with Education for Nature -- Vietnam (ENV). Additional funding and support for the Asian Turtle Program comes from Conservation International, the Turtle Survival Alliance, the Wildlife Conservation Society, Melbourne Zoo, the Turtle Conservation Fund, the Wade Foundation and the Bachelor Foundation.

Cleveland Metroparks Zoo is home to 3,000 animals representing 600 species from six continents. Committed to improving the future for wildlife, the Zoo runs conservation initiatives both locally and abroad, supporting field scientists and conservation efforts in Asia, Latin America and Africa.

Adapted from materials provided by Cleveland Metroparks Zoo.