[enviro-vlc] Future of Giant Turtle Still Uncertain [Yangtze giant soft-shell turtle]
vern.weitzel at gmail.com
Fri Oct 10 05:19:00 EST 2008
Future of Giant Turtle Still Uncertain
By JIM YARDLEY
Published: October 7, 2008
BEIJING — Wait until next year.
Video: A Symbol of Longevity on the Verge of Extinction
Qi Zhenglin/Wildlife Conservation Society, via Associated Press
An 80-year-old Yangtze giant soft-shell turtle, the only female known to exist,
was moved in May to a zoo in Suzhou to mate with a 100-year-old male turtle. So
far, no population increase.
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 a chance remained to
save her species.
In May, scientists 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 the
last known male of the species, though in recent months scientists 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 on May 7.
It was a meeting that carried some risk; males can be territorial and have been
known to attack other, unfamiliar, turtles. On top of that, neither turtle had
seen a member of the opposite sex in decades. But scientists say the pairing was
“It worked very well,” Mr. Kuchling said by telephone.
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.”
Mr. Kuchling said the female had been fed raw beef and pork, rather than a more
desirable diet of fish and crayfish.
“If the nutrition of the female is not right, then the eggs usually die,” he said.
Males of the species can reach 220 pounds, while females are usually about half
that size. The female from the Changsha zoo weighs about 90 pounds, while the
male from the Suzhou zoo weighs more than twice as much.
Xie Yan, the China program director for the Wildlife Conservation Society, said
she remained hopeful.
She said that 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. “The male and the female didn’t spend enough time together this
year,” she said. “This was the first time they mated. Next time will be better.”
The Yangtze giant soft-shell turtle is one of the largest freshwater species in
the world, though its population has been decimated by hunting and pollution.
Last year, scientists struggled to persuade either the Suzhou or the Changsha
zoo to allow its turtle to be moved.
Scientists had considered artificial insemination but decided the procedure
would be too risky. It became unnecessary when the Changsha zoo agreed to move
the female to Suzhou.
Now, 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 open again next May, during breeding season, and the two old turtles
will try once again.
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