The fate of a species is resting on the shells of two turtles at China's Suzhou Zoo.
n June, researchers collected eggs from the last mating pair of the critically endangered Yangtze giant softshell turtle (Rafetus swinhoei) in the hopes that at least one will be fertile.
The 220-pound (100-kilogram) freshwater giant, which spends most of its life burrowing in mud, was once common in its namesake Yangtze River, China’s Lake Taihu and Yunnan Province, and parts of Vietnam.
By the late 1990s, however, human encroachment and poaching for use of the shells in Chinese traditional medicine rapidly depleted the population. Now, a total of four animals are known—two wild males in Vietnam and the mating pair at Suzhou Zoo.
It’s the team’s sixth year of breeding the turtles at the zoo, which is not far from Shanghai. So far, none of the eggs have hatched.
Researchers can’t pinpoint the reason for the infertility, but they suspect a combination of factors, including poor sperm quality due to the male’s age—roughly a hundred—an improper mating posture, and stress on the female.
Because the turtles are the last in captivity and too much human interaction could kill them, sperm samples cannot be taken nor tests run. Still, scientists are hoping that this year will be the lucky one. (Related: "Pictures: Turtles Hunted, Traded, Squeezed Out of Their Habitats.")
"The resurrection of this iconic species in the wild, the largest freshwater turtle in the world, would be a symbol of hope," said Gerald Kuchling, founder of the Australia-based group Turtle Conservancyand a turtle-reproduction expert.
As is the case with many near-extinct species, by the time scientists realized the extent of the turtle’s decline, the species was almost gone.
In 2006, the U.S. nonprofit Turtle Survival Alliance asked Kuchling to establish the sex of the last three captive giant softshell turtles in China, which at the time lived at the Shanghai Zoo, Suzhou Zoo, and Suzhou’s West Garden Buddhist Temple. (Related: “6 of Nature’s Loneliest Animals Looking for Love.”)
When Kuchling landed in China in 2007, the Shanghai Zoo and Buddhist Temple individuals had already died. The Suzhou Zoo male was the last known Chinese survivor. Researchers sent an all-points bulletin to every zoo in the nation in the off chance a turtle had been misidentified.
Their call was answered: A photograph of a turtle at the Changsha Zoo looked promising. Kuchling, along with Lu Shunqing, China director for the Wildlife Conservation Society, traveled to Changsha, where they confirmed it was a Yangtze giant softshell—and a female to boot.
"It’s a bit miraculous we found her," said Emily King, the Suzhou Zoo breeding program’s field assistant.
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