Then, alluding to the Yangtze giant soft-shell, also known as the Rafetus swinhoei, she added:

“This turtle will be next.”

Surviving History’s Tides

Fifty-one years ago, a traveling circus performed at the new zoo in Changsha, the capital of Hunan Province in southern China. For a cash payment, the circus left behind a large female turtle. Zookeepers slipped the turtle into a large pond, where for a half-century it hibernated in winters and poked its pig-like snout above the water’s surface every spring. The walls of the zoo became the equivalent of a time capsule.

Outside, the convulsions of modern Chinese history were scarring an already damaged landscape. Under Mao, national campaigns were waged to kill birds and other animals perceived as pests. Widespread famines in the late 1950s and early 1960s drove desperate people to hunt or gather anything deemed edible, even tree bark.

Since the 1980s, the pressure has come from the rapid push for economic development. In recent years, turtle experts identified the Yangtze giant soft-shell as dangerously close to extinction. Inside the Changsha Zoo, zookeepers had no idea that experts were scouring China for the species. In fact, they knew very little about their female turtle. “We just treated it like a normal animal,” said Yan Xiahui, deputy director of the zoo.

The species was first identified as distinct in the 1870s. A British diplomat in Shanghai sent a specimen to the British Museum, where it was beheaded and pickled in a jar. Some experts debated whether it was part of another species, and for years it received little attention.

“It proceeded to be ignored by the world as if it didn’t exist for roughly 100 years,” said Dr. Pritchard, the American expert, who has seen the specimen in the British Museum.

With its wide, flat shape and leathery dorsal shell, the giant Yangtze males can weigh more than 220 pounds; females are usually smaller. By the 1990s, a prominent Chinese herpetologist, Zhao Kentang, had realized the significance of the turtle and tried in vain to persuade different zoos to bring the turtles together for breeding.

By 2004, after conducting field surveys in China and Vietnam, herpetologists concluded that six of the turtles were still alive. Three were in Chinese zoos in Beijing, Shanghai and Suzhou; two others lived in a Buddhist temple in Suzhou; and a sixth lived in a famous Vietnamese lake in the center of Hanoi.