Inside the high-tech plot to save the northern white rhino from extinction

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Immediately after the last white rhinoceros in the north of the world died on March 19, a team of veterinarians went to work. Within 30 minutes, they had collected tissue from the ears, gums, spleen, trachea and testicles of the 45-year-old rhinoceros, called Sudan. The valuable genetic material was put into a solution and then frozen in Ol Pejeta Conservancy in Kenya, where Sudan spent the last nine years of its life. Those cells could someday return the northern white rhinoceros to the brink of extinction.
Dozens of scientists from all over the world, from the USA UU Until Europe and Africa, they work together tirelessly to discover ways to breed rhinoceros embryos in the laboratory. The effort resembles in some way the popular extinction projects that try to resurrect the woolly mammoth or the carrier pigeon; everyone wants to reverse the extinction and, in some cases, repair the damage that humans have done.
"I think it's our responsibility."
The chances of success for the rhino are much greater: unlike the species that went extinct decades ago (or thousands of years!), The DNA and sperm of the northern white rhinoceros are safely preserved in different laboratories around the world. If it works, the project could bring back flocks of northern targets that used to roam the prairies of eastern and central Africa, where they were poached by their horns.
"They are on the verge of extinction only because of human activity," says Jan Stejskal, director of communication and international projects at the Dvůr Králové zoo in the Czech Republic, where Sudan lived until 2009. "If we have the techniques or methods to help them to survive, I think it's our responsibility to use them. "
Extinction has been a trope of science fiction for decades, but now science may have finally reached our imagination. Today, projects such as the Woolly Mammoth Revival led by George Church of Harvard are trying to use biotechnology to resuscitate the extinct species and repopulate the tundras and forests of Siberia and North America. It works like this: pieces of mammoth DNA are edited in the genetic code of your living cousin, the Asian elephant. A hybrid embryo would be grown on a surrogate mother of the Asian elephant, or an artificial womb, says Church, to give birth to a new mammoth-elephant animal.
Despite claims that the hybrid embryo could be created as early as next year, the project is far from resurrecting mammoth herds. However, it has started a heated debate over whether extinction technology should even be used. Many argue that money spent to bring back missing species should be dedicated to preserving those that still exist. Others criticize the ethic of resurrecting species whose habitats may have left and putting surrogate mothers at risk.

Photo: Jan Stejskal

Najin and Fatu, the only remaining white rhinos in the north of the world, at Ol Pejeta Conservancy in Kenya. | Photo: Jan Stejskal
It is estimated that raising a herd of northern white rhinos costs up to $ 9 million, according to the Dvůr Králové zoo, and much of the money comes from donations and zoo income. The San Diego Zoo, which is also involved in the project, says that an estimate is impossible since the necessary technology is still being developed. "Over the course of three years, the total annual budget has exceeded one million dollars," Stacey Johnson, corporate director of conservation and research at San Diego Zoo Global, tells The Verge in an email. But the northern white rhino project is fundamentally different from other projects like the Woolly Mammoth Revival, and that makes the money worthwhile, says Joseph Bennett, an assistant professor at Carleton University, who criticized the costs of extinction and he is not involved in the project of the northern white rhinoceros.
To begin with, unlike the woolly mammoth, the northern white rhino has not yet become extinct. Only two women remain: Najin and Fatu, both related to Sudan and living in the Ol Pejeta Conservancy under armed surveillance. While the habitat of the woolly mammoth is very different from what it was thousands of years ago, fragmented by roads and cities, for example, the habitat of the northern white rhinoceros still exists.
"It makes a lot more sense for me to work on something like something that went extinct 10,000 years ago, that could not even survive in a warm Arctic," says Bennett.
The white rhinos of the north have been extinct in the wild since 2008, but only because they were poached by their horns. And that makes humans responsible for their survival. "If … we are to blame for the extinction, we are also on the verge of finding a way to try to undo that extinction," says Douglas McCauley, ecologist and conservation biologist at the University of California at Santa Barbara, who is also been critical of the extinction projects. McCauley agrees with Bennett that trying to rescue the northern white rhino is "totally appropriate." Rhinos play an important role in the environment, dispersing seeds and maintaining vegetation, and as a result, rodents and snakes, under control. In addition, rhinoceroses are becoming extinct at this time. It's more like playing Noah than playing God, says McCauley.
"It's a bit more ethically clean," he says.
There is a more key difference between the white rhinos of the north and the mammoths: although we only have bits of mammoth DNA, we have a lot of complete genetic material, as well as sperm, from several northern targets. It is kept frozen safely in laboratories around the world.

Photo: Jan Stejskal

Sudan, the last male white rhinoceros in the north, died on March 19. | Photo: Jan Stejskal
In 1986, Oliver Ryder, director of conservation genetics at the San Diego Zoological Institute for Conservation Research, flew to the Dvůr Králové Zoo in the Czech Republic to collect Sudan skin cells. Sudan had been living there since the 1970s, as other white rhinos from North Africa were being exterminated by civil wars and poaching. At that time, Ryder was studying the genetics of the northern targets to determine if it was a different subspecies of the southern white rhinoceros, which is a bit larger and lives in southern Africa. (Yes they are). Sudan had never been anesthetized before, and Ryder remembers: "There was a tension."
The procedure was fluid, and the cells were eventually added to the Frozen Zoo, the collection of cells, eggs, sperm and embryos of approximately 1,000 species and subspecies, housed at the San Diego Zoo. At that time, Ryder did not know that these cells could one day be the key to rescuing the animals. "I was not so visionary, honestly," he says. However, I had the suspicion that they might be important in ways I had not yet thought of.
In 2015, Ryder, Stejskal and others met in Vienna, Austria, and developed a plan to use the genetic material and sperm taken from the northern targets to reverse extinction. The plan involves some options, with techniques that have been shown to work in humans and other animals, such as mice, but not rhinoceroses. "There may be obstacles that could be too difficult," says Stejskal. "In the case of the rhinoceros, you do not do it because you're sure you'll succeed, but you do it because you feel it's the right thing to do."
"You do it because you feel it's the right thing to do."
One option requires taking the frozen sperm and using it to fertilize rhinoceros eggs in a Petri dish. But there are some problems: although the technique has been used in humans, cattle and, more recently, in bison, it has never been done with rhinos, says Richard Vigne, CEO of Ol Pejeta Conservancy. The second problem is that there are no northern white rhino eggs. The female rhinoceroses are huge, and their ovaries are almost five feet inside their bodies, says Stejskal. To reach the ovaries, scientists must use a special tool with an ultrasound probe and a needle at the end to aspirate the egg cells. "You have to operate with this tool very carefully," says Stejskal. If the needle punctures what it is not supposed to, "it could have really serious consequences".
Stejskal and his colleagues at the Leibniz Institute for Zoo and Wildlife Research in Berlin have been working on more than a dozen southern whites to optimize a method for harvesting eggs. (None of the women can have babies, so it will not matter any confusion that could make them sterile.) And a similar job is happening at the San Diego Zoo. But it has not yet been tested on Najin and Fatu. The two remaining northern white females are too precious for any serious error, but the technique could be close to being ready: Stejskal says he hopes to try the procedure with Najin and Fatu in three or four months.
Meanwhile, there is option number two: make rhinoceros eggs and sperm in the laboratory. Theoretically, this can be done by converting the frozen rhinoceros cells into cells that can be transformed into any cell in the body, called pluripotent stem cells. These stem cells can become sperm and eggs. The sperm made in the laboratory is important because the frozen sperm collected directly from the animals may not be of high quality. When, for example, Sudan sperm was collected in 2014, it was already old, says Stejskal. But eggs made in the laboratory are the most important part: Najin and Fatu are the only whites from the north who still produce eggs. "If they were to die today, their eggs would go with them," says Vigne. They are also mother and daughter. So the new eggs will have to be made from other rhinos, otherwise the whites from the north will be too inbred to thrive.
The stem cell technique, which has nothing to do with cloning, has already been used in Japan to create living mice. Rhinoceroses are much less studied than mice, but Jeanne Loring, director of the Center for Regenerative Medicine at the Scripps Research Institute, has already transformed white rhinovirus cultures from the north into pluripotent stem cells. His laboratory even converted those stem cells into nerve cells and into heart cells in a Petri dish, she says. So she is sure that she will also be able to produce sperm and eggs. "It's just another type of cell, so we do not consider it an overwhelming challenge," says Loring. "We have to do it with a lot of trial and error."
Whichever technique the scientists use to create the northern white rhinoceros embryos, the plan is to implant them in the southern targets of the females kept in zoos. The two rhino subspecies are genetically so similar that southern white mothers should be able to give birth to a white baby from the north without too much trouble, says Ryder. The first calf could be born in a few years, according to Stejskal. But "it's hard to say because there are so many steps," he says. "There may be obstacles that we have no knowledge of."

Photo: Jan Stejskal

Sudan in the Ol Pejeta Conservancy in Kenya. | Photo: Jan Stejskal
Raising a herd of northern targets and reintroducing them in Africa will be difficult, and the project is risky. The technology may not work, and then millions of dollars could have been wasted. But that's fine, says Henry Greely, director of the Center for Law and Biological Sciences at Stanford University, who is not involved in the project. Pharmaceutical companies spend millions trying to develop new medicines, but often fail. "That happens a lot in science," says Greely. In addition, the longer it takes to create a herd, the harder it will be to reintroduce it into the wild, says McCauley at UCSB. "Ecosystems change and the longer you wait, the more uncomfortable it is to put a species back in its place," he says.
"That would be the most dramatic statement."
Still, the project is worth it, says Vigne in Ol Pejeta. It's not just about reversing extinction, "it's about preserving a genetic code that has evolved over millions of years," he says. It is about preserving the large and charismatic animals that enrich our planet. For Bennett, at Carleton University, the project could even function as "an effective poster child" that mobilizes the public about conservation and could encourage people to donate.
For many of the scientists involved in the project, it is a matter of responsibility. The white rhinos of the north are almost extinct because humans shot them dead, so it is up to us to correct our mistakes. "The northern white rhino is emblematic of our times, about the impact of humans on wildlife," says Ryder. "That would be the most dramatic statement of what we could do in our time to reverse something that would otherwise seem like a sad commentary on our species."

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