BEIJING – Wait until next year.
Scientists trying to save one of the world's most endangered species of freshwater turtles say waiting is their only recourse after a complicated attempt to mate two elderly turtles during this year's breeding season ended without producing any offspring.
The fate of the Yangtze giant soft-shell turtle seems especially uncertain because only one female is known to exist – an 80-year-old turtle with a leathery shell that lived without notice for a half century inside a zoo in Changsha, the capital of Hunan Province in southern China.
Only when scientists discovered her existence last year did it become clear that she represents perhaps the only chance to save her species.
In May, scientists loaded the female turtle into a van and drove her more than 600 miles to a zoo in the city of Suzhou. There, a male turtle estimated to be 100 years old awaited her. He had been considered the last known male of the species, though in recent months scientists have discovered two more males in Vietnam.
Gerald Kuchling, a prominent herpetologist helping to oversee the mating program, said the male and female turtles were introduced to each other May 7.
It was a meeting that carried some risk; males can be territorial and have been known to attack unfamiliar turtles. Nor had either turtle seen a member of the opposite sex in decades. But scientists say the pairing was a success.
“It worked very well,” Kuchling said in a telephone interview. “The whole mating and pairing worked very well.”
June seemed to bring good news: The female produced roughly 100 eggs, and about half appeared to be fertilized. But scientists now say the embryos apparently died in early development. A recent posting on the Web site of Turtle Survival Alliance, a global network focused on protecting endangered turtles, said “a number of the eggs had very thin or cracked eggshells, suggesting that the diet of the animals prior to breeding was not optimal.”
Kuchling said the female had been fed raw beef and pork, rather than a more desired diet of fish and crayfish. “If the nutrition of the female is not right, then the eggs usually die,” he said.
Xie Yan, the China program director for Wildlife Conservation Society, said she and others involved in the turtle-mating project remained hopeful, despite the setback this year.
She said the diet for the female had already been changed and that her general health was considered good. The discovery of two more males is also good news, she added.
“I still feel optimistic,” Xie said. “The male and the female didn't spend enough time together this year. This was the first time they mated. Next time will be better.”
The Yangtze giant soft-shell turtle is considered one of the largest freshwater species in the world, though its population has been decimated by hunting and pollution.
The two turtles live in adjacent ponds at the Suzhou zoo. The ponds are connected through a small channel, which is blocked by an underwater door. That door will come open again next May, during breeding season, and the two old turtles will try once again.
