JIANGSU, East China — Imagine that the human species has been decimated to one man and one woman. Their names are no longer relevant, as they can simply be referred to as “he” and “she.” The future of the entire species depends on their willingness — and ability — to mate and produce offspring.

This is what’s happening to the Yangtze giant softshell turtle, or Rafetus swinhoei. Scientists, the media, and even the turtles’ caregivers have long stopped calling 110-year-old Susu and 90-year-old Xiangxiang by their names, simply referring to them as “the male” and “the female.”

They are the last two Yangtze giant softshell turtles known to still live in China. Another one has been located in a lake in northern Vietnam, while a second turtle died last year. There’s a small chance that others might exist in the wild somewhere, though nobody knows for sure. The International Union for Conservation of Nature lists the species as “critically endangered,” indicating that it faces an extremely high risk of extinction. Scientists have gone so far as to call the turtles the “zombie species,” as the few remaining individuals are living long lives but have stopped reproducing.

Experts believe that artificial insemination might hold the key to altering the fate of the species. Attempts to mate the Chinese pair started about 10 years ago, when the female turtle was moved to Jiangsu province to live with the male turtle in an enclosure at the Suzhou Zoo. Scientists hoped that once they were living together, the two would mate and eventually reproduce.

Male and female did indeed mate, but it never resulted in offspring. Lü Shunqing, a zoologist involved with the turtle breeding program, told Sixth Tone that despite the female’s age, she still produces eggs. The male, however, badly damaged his reproductive organs in a deadly fight in which he killed another Yangtze giant softshell turtle. Now, his sperm count and motility are so low that artificial insemination appears to be the last hope.

After two failed attempts in 2015 and 2016, experts from China, the U.S., Germany, and Australia tried a third time in April to extract sperm from the male and use it to inseminate the female.

So far, it’s unclear whether the insemination was successful. “Even though we have applied the most advanced technology, we still cannot guarantee the success of fertilization,” Lü said. Last year, sperm was surgically injected into the female’s oviducts with a long syringe. This time, the scientists inserted the semen with flexible catheters, a more advanced technology that gets the sperm closer to the ovaries and is considered less invasive and risky.

“If we failed again this time, then it is probably because of the animal itself, not the technology,” Lü said. Successful artificial reproduction among giant turtles is unprecedented in China.

“Artificial insemination is always risky and particularly difficult with very large turtles that have complicated reproductive systems and have to be anesthetized,” Eric Goode, president of the global conservation organization Turtle Conservancy, told Sixth Tone in an email interview.

Wen Cheng, director of urban planning and habitat restoration programs at Beijing-based environmental group Shanshui Conservation Center, echoed this statement. “[Artificial insemination] can cause possible injury to the animals,” he said, explaining that sperm collection requires the male turtle to undergo electrical stimulation, which causes stress and involves a long recovery period. Even in healthy males, electrical stimulation doesn’t yield high-quality sperm, Wen said. However, he acknowledged, there are hardly any alternatives for saving the valuable species.

In Chinese culture, turtles are considered sacred animals that symbolize longevity, wisdom, and wealth. They have been targeted by hunters in the past, as they made for popular pets and were often found on dinner menus.

Human activities have pushed the Yangtze giant softshell turtle and other aquatic species to the brink of extinction. Industrial development and rapid population growth have polluted and encroached on the turtles’ natural habitat in Yangtze River drainage networks. On the Red River, which runs through southern China and northern Vietnam, sand dredging and the construction of hydropower dams have altered another habitat.

For half a century, not a single Yangtze giant softshell turtle has been found in the Yangtze River drainage area, despite repeated survey efforts in the region. Fishermen have reported seeing the turtles in the Red River, but experts were unable to confirm these sightings. “It was like trying to find a needle in a haystack,” said Wen, who participated in one of the surveys. If any are left, it’s no more than a handful, and they haven’t reproduced, Wen wrote in a scientific paper on the species.

Suzhou residents like Zhou Ziyu have fond memories of the male turtle. The now 31-year-old still remembers the first time he saw the turtle: Zhou was just a little boy and was shocked by the size of the 74-kilogram creature swimming in its pool. “It was so big,” Zhou recalled. “Adults even fooled me, saying that the turtle eats children.”

Zhou visited the Suzhou Zoo with his 2-year-old son on a recent afternoon, but the two didn’t get to see the rare turtles. Both male and female are now at a facility belonging to the zoo but closed to visitors, awaiting the completion of their new enclosure following the zoo’s recent move, which also gives the scientists a chance to properly observe the female. If the artificial insemination produces eggs, the conservation groups working on the project have agreed to raise the turtles’ offspring in captivity — at least until the population has grown large enough to be reintroduced into the wild.

For the species to then have a chance at survival, better laws must be enacted to protect the turtles, said Peter Paul van Dijk, the director of the Turtle Conservation Program at Global Wildlife Conservation who has focused on tortoise and freshwater turtle conservation in Asia for more than two decades.

The first step, however, is raising population numbers. The artificial insemination program, said van Dijk, is “highly significant” to this effort.

Although their chance at success is small, the scientists working on the breeding program said that they won’t give up unless one of the turtles dies. “Every species is considered priceless, as their genetic information has unlimited value,” Lü said. “Even with 0.1 percent hope, we make 100 percent effort.”

In Suzhou, where the turtles are currently enjoying their privacy in their temporary enclosure, there’s still a way to see the species — albeit not real individuals. Xiyuan Temple was once home to two Yangtze giant softshell turtles, and when they died, they were immortalized in the form of bronze statues that now stand beside the fangsheng pool into which live animals are released in Buddhist rituals.

Worshippers who come to the temple will rub the turtles’ bronze shells, place coins on their heads, and bow devoutly to the statues. Ironically, most visitors are seeking blessings of good fortune from a species that is on the brink of destruction. Few have seen a real Yangtze giant softshell turtle for themselves.

When asked what she was praying for, an elderly woman answered: “Longevity.”

Editor: Denise Hruby.

(Header image: The female Yangtze giant softshell turtle sits in her enclosure at the Suzhou Zoo in Jiangsu province, May 9, 2008. Liu Yan/VCG)