Science
Scientists Make Novel Attempt to Save Giant Turtle Species
The Yangtze giant softshell turtle has been driven to the brink of extinction. Credit Gerald Kuchling/Turtle Survival Alliance
In May, an international team of scientists, veterinarians and
zookeepers gathered at the Suzhou Zoo near Shanghai. Their desperate
mission: to attempt the first artificial insemination ever of a
softshell turtle, saving the species from oblivion.
“Even
if we get just one or two hatchlings, I will be very happy,” said
Gerald Kuchling, a project leader for the Turtle Survival Alliance, a
nonprofit conservation organization. “Even a single one would give hope
for the recovery of this magnificent animal. It would be a turn.”
Quite a turn, actually. The Yangtze giant softshell turtle
— thought to be the largest freshwater turtle in the world — was once
common in the Yangtze and Red Rivers. But by the late 1990s, pollution,
hunting, dams and development had driven it to the brink of extinction.
There
are only four known specimens remaining, and only one female — an
85-year-old resident of the Suzhou Zoo. For years, biologists have been
trying to coax her and her 100-year-old mate to produce hatchlings. So
far the pair have disappointed scientists, with the female laying clutch
after clutch of unfertilized eggs.
She
was discovered only in 2007, three years after the sole other known
female died at the Beijing Zoo. Desperate to find another, Dr. Kuchling
and Lu Shunqing, a turtle specialist from the Wildlife Conservation
Society’s China branch, had asked every zoo in the country to send them
photographs of any large softshell turtles in their possession.
One
image, taken at the Changsha Zoo in Hunan, caught their eye, and days
later, they arrived to examine the turtle. It was indeed a Yangtze giant
softshell turtle and, crucially, a female. She had once been part of a
traveling animal exhibition, they learned, and became a permanent
resident of the zoo shortly after the end of the Chinese Revolution in
1949.
Dr.
Kuchling and Dr. Lu arranged for her transport to the Suzhou Zoo, where
they hoped she and the zoo’s male specimen would begin producing more
of their kind. To their delight, the animals did appear to mate, and
that summer, the female laid around 180 eggs.
But none proved fertile,
a disappointment that would repeat itself for six years. “The
conservation world was holding its breath,” said Rick Hudson, the
president of the Turtle Survival Alliance. “It’s been a lot of
frustration since.”
Scientists
decided to intervene. On May 6, Dr. Kuchling and Dr. Lu, with a team
that included turtle experts from the United States, drained the male’s
pond and used a cargo net to wrangle the 140-pound turtle onto a stack
of car tires that served as a makeshift examination stand. Putting him
under anesthesia, the scientists used an electrical probe to induce a
partial penile erection.
Normally,
the penis of the Yangtze giant softshell turtle looks a bit like a
medieval weapon. Equipped with fleshy spikes, protuberances and lobes,
it is designed to navigate the female’s equally complex reproductive
organ, located inside a byzantine chamber called the cloaca.
The problem became immediately clear to the scientists: This turtle’s penis was mangled.
Two
decades earlier, another Yangtze giant softshell turtle had been added
to the male’s pond in an attempt to mate the animals. The second turtle
turned out to be male, as well, and the two fought. The second male was
killed, and the victor suffered serious damage to his shell and, it now
appears, to his reproductive organ.
The
team also examined the male’s sperm — extracted using electrical
stimuli — and finally discovered good news. While motility was low, the
sperm were viable. The scientists decided to proceed with artificial
insemination of the female.
With
no case studies to go on, the team had to improvise. Dr. Kuchling
examined the sedated female’s cloaca with a fiber-optic endoscope to
locate the compartment leading to her oviducts. Then Barbara Durrant,
the director of reproductive physiology at the San Diego Zoo’s Institute
for Conservation Research, deposited the semen.
“It
was just a matter of delivering the semen through a small plastic tube
into what we think is the correct place,” she said. “Unfortunately,
there just hasn’t been that much basic reproductive physiology work done
in turtles and tortoises.”
Even
if it’s guesswork, artificial insemination may be the only chance to
save the species. Two other male Yangtze giant softshell turtles are
believed to be in Vietnam — one in Hoan Kiem Lake, in the center of
Hanoi. But those animals “are pretty much off limits for any
non-Vietnamese,” Dr. Kuchling said, and so a collaborative breeding
program seems unlikely.
A
handful of Yangtze giant softshell turtles may remain in the wild;
tentative sightings have been reported in a dam reservoir on the Red
River in Yunnan Province. Conservationists, however, are not betting
that another male will be captured anytime soon.
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Now
the wait begins. When the female lays her first clutch of eggs,
probably by late June, the scientists will know if this first effort was
fruitful.
“Nobody
has ever done this before, and it’s probably a long shot,” Dr. Kuchling
said. “But we are all hopeful, and if it doesn’t work this time, we’ll
definitely try again. Despair is not an option.”
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