Scientists make novel attempt to save giant turtle species

NEW MEASURES Scientists are attempting the first artificial insemination ever of a softshell turtle, saving the species from oblivion, learns Rachel Nuwer

Earlier this month, 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 non-profit conservation organisation. “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 larges 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 unfertilised eggs.

She was discovered only in 2007, three years after the sole other known female died at the Beijing Zoo. Desperate to find another, Gerald 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.

Gerald and Shunqing 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, Gerald and Shunqing, 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 anaesthesia, 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.

Lost in combat
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. Gerald 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,” Gerald 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.

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,” Gerald said. “But we are all hopeful, and if it doesn’t work this time, we’ll definitely try again. Despair is not an option.”