The Last of His Kind

Bonus chapter from Poached: Inside the Dark World of Wildlife Trafficking

Reported April-September 2016

Sudan, the world’s last male northern white rhino, at his final home at Ol Pejeta Conservancy in Kenya.

Sudan, the world’s last male northern white rhino, at his final home at Ol Pejeta Conservancy in Kenya.

I met Sudan, the world’s last male northern white rhino, briefly in 2016 at Kenya’s Ol Pejeta Conservancy. Weeks later, I followed through on a mental promise to look into the old rhino’s tale. Had I known the details in advance, I would have lingered longer by his side.

The conflict-filled 1970s and 1980s were a terrible time to be a rhino in Africa. Poaching had reached epidemic proportions and populations across the continent were plummeting. It was in these turbulent years that Sudan was captured, at the bidding of a Czechoslovakian man named Josef Vágner.

A dreamer, adventurer and animal fanatic, surviving photos of Vágner show a brawny man with Sean Connery-like features, often embracing various four-legged friends: leaning in for a giraffe kiss, giving a rhino a treat or cradling a furry baby as though it were his own. As he wrote in one of his books, Vágner considered animals to be “our partners in life.”

In 1965, Vágner become director of the Dvůr Králové Zoo in what is now the Czech Republic. Despite the position, he spent up to eight months of the year in Africa, justifying his absence by collecting multitudes of specimens to bring back home—enough, he hoped, to “allow [the animals] to maintain the social systems that they have in the wild.” He eventually imported some 3,000 living creatures, two-thirds of which became permanent residents at his zoo. “This wasn’t like spiders or something,” pointed out Jan Stejskal, the zoo’s current director of international projects. “Most of these were large ungulates and big mammals.” 

To this day, Vágner’s wild animal shipments remain the largest ever undertaken. Some of the captives voyaged to Europe on ships crowded with crates, like a modern day’s Noah’s ark. Others flew—leading to a few comical mishaps. During one fated 1968 air shipment, Vágner received a telex from Zurich: “Monitor and crocodile broke open box and ran round luggage hold.” Rather than deal with this mess, the flabbergasted Swiss simply shut the hatch and sent the plane on its way to Copenhagen. Nevertheless, all the cargo arrived safely. Indeed, Vágner was always quick to point out that his losses over the years totaled just 2.8 percent, compared to up to 30 percent for similar expeditions of the day.

Josef Vágner on a wildlife collecting expedition in Africa. Photo courtesy Lenka Vágnerová

Josef Vágner on a wildlife collecting expedition in Africa. Photo courtesy Lenka Vágnerová

In the early 1970s Vágner set his sights on an exceedingly rare specimen: the northern white rhino. International zoos held fewer than a dozen of the coveted subspecies, but Vágner was determined to add a few more to that list. He linked up with big-game trapper Richard Chipperfield, who had negotiated with the Sudanese government to purchase six northern white rhinos during the 1973/1974 capture safari season.

Sudan had just emerged from nearly two decades of civil war, and things on the ground were far from settled. “We put our lives at risk, specifically to collect and preserve those rhinos,” said Peter Litchfield, one of Chipperfield’s employees. He and his colleagues were accustomed to dealing with difficulties and danger, however: they normally operated in Uganda, where then-President Idi Amin was wreaking havoc under a deadly military dictatorship.

Using a 1945 map (the most up-to-date they could find), they headed to Sudan’s Shambe wetlands, where around 200 northern white rhinos lived. “Not one road or bridge was there, so a trip of 420 miles took us four days,” recalled Annie Olivecrona, a Swedish conservationist now based in Kenya, who worked for Chipperfield from 1968 to 1975. The team also had to stop at every police post in every village along the way, adding hours to the already arduous journey. When they finally reached the field site, Olivecrona built a camp on the edge of the Nile, beneath the only large tree in sight and near an old water hole indicated on the map. “Water and shade: that is the key to a camp,” she said. 

Vágner and his son arrived after Christmas, and while they flew overhead taking photos, Chipperfield, Litchfield and their colleagues pursued the rhinos. Once the animals sensed danger, they tended to head for the thickest bush they could find. Chipperfield navigated through by vehicle while Litchfield tried to ensure the pole and rope he used to snare the rhinos did not become entangled in the branches and thorns, even as they tore at his clothes and body. “Opportunities to rope the animals were few and far between—just split seconds to deploy the noose would be all I had,” Litchfield said. “Failure would mean the rhino was lost, and we would need to locate a different animal and start again.”

In the end, they achieved their goal, capturing seven rhinos in all—three males and four females. As per the agreement with the Sudanese government, one male remained at a small zoo in Khartoum (he was later relocated to the San Diego Zoo). The rest—including a two-year-old male calf who Vágner named Sudan—were destined for Europe. As Vágner later wrote, getting them out of Africa and into Europe “was the most difficult task we had ever faced.” Notably, though, he did not take part in that task. To his distress, he was forced to return home by the increasingly stringent communist regime in Czechoslovakia.

“Joe always had some ‘spies’ with him, at least two, and they were listening to every word we said,” Olivecrona recalled, citing an earlier trip Vágner had joined her and Chipperfield on in Uganda. “Sometimes we got them drunk so they would go to bed and we could sit around the campfire talking without having to think about what we said about his country and other political things. I think he wished it had been his son down there doing the catching, and also that the two of them would have been allowed to be there the entire time, but this was not so. Joe had a seriously difficult time with the regime in his country. They did everything to bring him down.”

With Vágner back home in Czechoslovakia, Olivecrona, Litchfield and their colleagues were left to deal with the rhinos, which they wound up having to sneak out of the country on lorries (the authorities in Juba would not to stamp Olivecrona’s exit visit unless, she said, “I did things I refused to do with the chief immigration officer”).  After making it across the border to Uganda, they arranged for the rhinos to travel by train to Mombasa, and then to board a transoceanic freighter for the long voyage around Africa and on to northern Europe. In Hamburg, they were sent by barge down the Elbe River to the Dvůr Králové Zoo, finally ending their nearly 14,000-mile journey.

Vágner had big plans for Sudan and his compatriots. He strongly believed that zoos should help to protect species, and he quickly set about fulfilling that mission to the best of his abilities. Ultimately, he wished to breed northern white rhinos and eventually send them home to Central Africa, once conditions were safer. In 1980, he and his staff took a first step toward realizing that goal when they welcomed into the world Suni, the first northern white rhino calf ever born in captivity.

The celebrations, however, were hampered by growing hostilities against Vágner. He hosted a weekly television show about wildlife and had become a popular figure in his country—something that didn’t sit well with the Soviet Bloc Czechoslovakian authorities. “The communist regime in Czechoslovakia did not allow anyone to derogate from ordinary, grey habits,” said Lenka Vágnerová, Vágner’s daughter. “His success and popularity with the nation aroused envy and hatred.”

The authorities began making Vágner’s life difficult. After an investigation of the zoo’s funds failed to reveal any dirt, the State Veterinary Administration decided to euthanize the zoo’s 49 “healthy, gorgeous” giraffes, Lenka said—the largest herd outside of Africa. Conveniently, Vágner was out on an expedition to India when the authorities came in one night, unannounced, and shot all 49 animals. When Vágner returned and demanded an explanation, officials claimed that the giraffes were infected with some sort of disease that could spread to livestock. Lenka maintains to this day that this was never proven, and that the giraffe execution was in fact an act of revenge.

In 1983, Vágner finally gave in and retired. There was no denying that the many injuries he had acquired chasing animals in Africa—rib fractures, damaged joints, a fractured pelvis, hepatitis, malaria and more—were starting to catch up with him. More than that, though, he was tired of fighting. His friends and family agreed that retiring voluntarily was better than the alternative. As Lenka said, “He would sooner or later be destroyed by his enemies, and with him, the entire family, too.”

Josef Vágner in his winter years. Photo courtesy Lenka Vágnerová

Josef Vágner in his winter years. Photo courtesy Lenka Vágnerová

Vágner’s personal story largely ended there. When the Iron Curtain fell, he briefly pursued a stint in politics, but soon went into seclusion. He passed away in 2000, aged 71, from total organ failure.

His conservation legacy, however, lived on. Dvůr Králové Zoo oversaw the birth of three more northern white rhino calves, the most recent of which, Fatu, was born the year of Vágner’s death. Dvůr Králové remains the only facility that has ever managed to breed northern white rhinos in captivity, but staff there still wish their output had been higher. Try as they might, further births eluded them. It may be, Stejskal suggested, that northern white rhinos that spend too much time in captivity together lose interest in each other. Yet unlike southern white rhinos, attempts at artificial insemination proved fruitless as well.

In Africa, on the other hand, northern white rhinos were having no problems reproducing—but war was and poaching were increasingly threatening their survival. Kes Hillman Smith, an English-born conservationist who moved to Kenya in 1973, was at the forefront of efforts to save the subspecies. She’d originally been hired by Iain Douglas-Hamilton to help with his ground-breaking elephant surveys in the 1970s. While counting live and dead elephants from above, though, she couldn’t help but notice another uncomfortable fact: there were a lot of rhino carcasses down there, too. In 1978, the New York Zoological Society (now the Wildlife Conservation Society) tasked her with leading the first pan-African rhino survey.

Later that year, Kes created and chaired the IUCN’s first African Rhino Specialist Group. She and her colleagues classified African rhinos into three groups: black rhinos, southern white rhinos and northern white rhinos. The group decided to focus their resources on northern white rhinos because they were the most imperiled. Kes and a colleague managed to scrape together some funding and settled on a research site at Garamba National Park in what was then Zaire—one of two known remaining strongholds for the subspecies. They had also hoped to work in Shambe, where Olivecrona had helped catch Vágner’s rhinos a few years before, but Sudan had just descended yet again into civil war.

In 1984, Kes moved to Garamba full-time with Fraser Smith, a fellow researcher who would later become her husband. The pair took to it immediately. “Initially I thought I’d be there for a year, but we ended up there for 22 years,” she said. “And even then I didn’t want to leave.” A World Heritage site larger than Rhode Island, Garamba was an easy place for a nature-lover to fall for. 

Counting Garamba’s rhinos was one of the first orders of business. Kes discovered that there had been two devastating waves of rhino poaching, the first during the Simba Rebellion in the early 1960s, after the country gained independence from Belgium, and the second in the late 1970s. Systematically combing the park by air, in 1983 she and Fraser could find just 13 to 20 northern white rhinos. They weren’t deterred, though. They set up constant monitoring and protection in the southern section of the park—a “spectacular wide open grassland,” as Kes described it, where the rhinos concentrated and reproduced well.

Things looked very promising at first. Under the team’s careful watch, both rhino and elephant populations began to rebound, doubling by 1992. By then, Kes knew each rhino by sight and name, and she was never more excited than when a new calf appeared. During one aerial survey, she spotted a baby rhino and its mother being chased by hyenas and couldn’t resist swooping in for a rescue—and incident she fondly recalled in her book, Garamba: Conservation in Peace & War. “Despite the objective non-intervention principle that biologists are supposed to have, a young Northern White Rhino was too precious to leave to such a fate,” she wrote. “I lined the plane up between the rhinos and hyenas and dived down, turned and dived again. In the face of such unfair intervention, the hyenas gave up.”

Garamba National Park. Credit: Nuria Ortega

Garamba National Park. Credit: Nuria Ortega

These happy days were not to last, however. In the early 1990s, ongoing civil war in Sudan drove 80,000 refugees into Zaire. Many were armed, and many settled in the areas surrounding Garamba. In 1996, Kes discovered the first poached rhino—a male who had been trying to expand his territory north. He was soon followed by a pregnant female, her carcass found riddled with bullets. Larger and larger groups of poachers began to invade the park, some bringing along hand grenades and rocket launchers in addition to ever-present AK-47s. They advanced south like a slowly rising tide, inching their way closer to the rhinos.

Later that year, Rwanda invaded and war formally broke out in Zaire. A local rebel leader named Laurent Kabila overthrew President Mobutu Sésé Seko, and mass chaos ensued. Rape, looting and murder were commonplace throughout the country, which Kabila renamed the Democratic Republic of Congo (DRC). Kabila’s soldiers reached Garamba in February 1997, putting an end to all anti-poaching efforts. When Kes and Fraser managed to carry out an aerial survey in July, they were heartbroken to find “fresh carcasses littering the park”—though most of the causalities were species other than rhino. Unbelievably, at least 24 northern white rhinos, including five new babies, were still hanging on. “Rhinos, being difficult to find, were not so hard hit,” Kes said. In contrast, elephant populations were reduced by half; hippos by three-quarters; and buffaloes by two-thirds.

A very brief reprieve to the fighting allowed Kes, Fraser and their colleagues to begin picking up the pieces, reequipping staff and getting the anti-poaching unit back into full force. But in August 1998, barely a year after the First Congo War concluded, the country yet again descended into violence. Some 5 million people would lose their lives by the time the Second Congo War ended in 2003—including Kabila, assassinated by one of his own child soldiers. Garamba, meanwhile, fell into the hands of Ugandan forces, and Kes and Fraser were forced to briefly evacuate to Kenya.

They weren’t the only dedicated expatriate conservationists working in the DRC at the time; there were also five other World Heritage sites staffed by now-exiled foreigners. Together, they proposed a new group dedicated to preserving biodiversity in regions of armed conflict—the first organization of its kind, which Kes coordinated. Tapping into funds originally donated by Ted Turner, the United Nations Foundation awarded the program $4 million, three-quarters of which went to keeping the field staff back in the DRC paid and working. The United Nations affiliation also enabled the researchers to call together self-styled Ministers of Environments from each part of the politically divided DRC for a discussion about conservation. Any promise of cooperation quickly disintegrated, however, when Ugandan troops pulled out and two tribal factions turned on each other. The situation further deteriorated as “young, ambitious men who had tasted sudden power tried to maintain their mini-war lord status in various ways,” Kes said. As she learned from that experience, “Sometimes it’s easier to deal with a situation when you know who your main war lords are.”

The United Nations project had enabled the Garamba team to maintain and, in some cases, even increase the rhino and other wildlife populations through the civil war, but a cease fire in neighboring South Sudan brought a new enemy: northern Sudanese hunters on horseback. “Fierce, ruthless and traditionally skilled elephant poachers,” the horsemen had left a wake of death in Darfur, Chad and the Central African Republic, Kes wrote. Now, they had come for Garamba’s animals, too.

The park’s rangers were quickly overwhelmed. In April 2003, Kes counted 30 rhinos, but by July the following year, numbers were down to 17. Kes collected and identified the skulls of the animals she knew so well: Notch, Kondo Akatani and others. One female’s skull was even accompanied by that of her tiny calf. “I cried—and was laughed at by the bodyguard of the new warden,” she bitterly recalled. “To him, they were just bones.”

With the rhinos facing certain doom, an emergency meeting was called. The International Rhino Foundation, Garamba’s main supporter, proposed one last-ditch plan: relocate five of the remaining animals to a safe place where they could live and breed until peace returned to Garamba. All the other donors agreed, and Kenya, with its long history of conservation and relative safety, was the obvious choice for a relocation site. The team settled on Ol Pejeta for its exceptional security, and managers there began making preparations. Meanwhile, the DRC’s president and four vice presidents all voiced their support, and an agreement was drafted guaranteeing that the translocated rhinos would remain their country’s property. It was “all hunky-dory,” as Kes said: Garamba would continue to receive critical support from its donors, and the northern white rhinos would have a chance at survival.

Very suddenly, however, the plan unraveled. The DRC’s minister of the environment—who was being fed stories of the rhinos being sold to Kenya to boost the other country’s tourism—pulled out of the agreement. The local press ran with the story, claiming that Kenya was stealing the DRC’s rhinos. People were so irate that mob violence broke out on several occasions. With elections coming up, the other officials grew wary of having their names associated with something so controversial. One by one, they withdrew their support.

This tragic turn paralleled the situation in 2000 in Cameroon, when officials refused to issue permission for the last western black rhinos to be relocated to safety. Three years later, the animals had disappeared, and in 2011, their subspecies was officially declared extinct. Now, history was repeating itself in the DRC. In 2012, researchers spotted the last northern white rhino ever sighted in the wild. With no more rhinos left to protect in Garamba, the International Rhino Foundation withdrew its support for the park, and Kes and Fraser had little choice but to leave. “Garamba was home,” Kes said sadly. “It was wonderful, and we all fought for it.”

Kes is based in Nairobi these days, though she has returned a few times to the park where she spent much of her life. Even now, during those brief visits, she can’t help but look for signs of the rhinos. “I still hope there are some northern white rhinos hiding out in the bush,” she wrote in her book. But even if that is not the case, Garamba, at least, “is still intact and beautiful.”

Vágner, of course, predicted this sad development. It was one of the reasons he brought northern white rhinos to Europe in the first place, and his contributions to keeping the subspecies alive continue today. After much internal strife, in December 2009, the Czech zoo keepers opted to transfer Sudan, Najin, Fatu and Suni (who died in 2014) to Ol Pejeta, with the hope that something about being back in their scrubby home turf would trigger a primal desire to reproduce.

A rhino transfer at Ol Pejeta Conservancy in Kenya. Credit: David Hambridge

A rhino transfer at Ol Pejeta Conservancy in Kenya. Credit: David Hambridge

Of the four rhinos transferred, Sudan in particular took to his new surroundings. Perhaps the smells, sights and sounds of Africa stirred long-ago memories in the now elderly rhino. The females also grew visibly healthier. “It was pretty clear that instinct was enough to enable them to adapt very quickly to the environment in which their species had evolved,” said Richard Vigne, Ol Pejeta’s CEO. 

Mating, however, was not in the cards. Sudan is no longer the rhino he once was: an examination of his sperm revealed a pittance of frayed cells. Even if that were not the case, though, he is Najin and Fatu’s father and grandfather, respectively—so hardly an ideal candidate for siring their offspring. And while Najin and Fatu’s eggs are probably fine, motherhood for them, even with donor sperm, turns out to be impossible. A mystery infection left Fatu with a pathologically warped uterus, while Najin has gimpy hind legs—the result of an overzealous encounter with a male southern white rhino. Should another two-ton bull attempt to mount her, or should she be subjected to the weight and strain of pregnancy, her tendons would likely permanently rupture. 

Broke-down sperm, a bum uterus, delicate ankles and a whole lot of incest: given that laundry list of setbacks, conservationists could not be blamed if they threw in the towel on this one. But that is not how things are going to go. A motley crew of rhino-loving scientists devised an unorthodox plan of attack for saving the subspecies—one that combines cutting-edge cellular technology and good old-fashioned animal husbandry. 

“If you asked me four years ago, I would have said, ‘No, we have no chance,’” said Thomas Hildebrandt, head of the department of reproduction management at the Leibniz Institute for Zoo and Wildlife Research in Berlin, who I originally interviewed for a PBS Nature feature about the rhinos. “But now we’re able to pair classic reproduction techniques like semen collection, artificial fertilization and embryo transfer with new stem cell technologies. Together, that’s a totally new dimension.”

Step one in the process is figuring out how to safely and effectively harvest oocytes from Najin and Fatu, a task that largely falls to Hildebrandt. Once that’s done, he and his colleagues will bypass Sudan’s subpar sperm in favor of samples from four other northern white rhinos kept in cold storage at the Genome Resource Bank in Berlin. Though long dead, those males’ supernatural semen may be key to bringing their kind back from the brink.

Assuming egg and sperm can be coaxed into coupling in their petri dish bed, researchers will then turn their sights to a healthy southern white rhino surrogate. Decades ago, livestock reproduction scientist Cesare Galli helped create the first in vitro cows and horses. A fan of challenges, Galli agreed to help out with the rhinos because he liked the idea of working on something “worthwhile and useful.” Success depends on whether he’s able to figure out the optimal culture conditions for the oocytes and embryos, and also on how many viable eggs Hildebrandt manages to extract from Najin and Fatu. “If you end up with just one egg out of an animal, there’s little you can do,” Galli said. “Or they might be too aged, like taking eggs from a woman nearing menopause.” Despite these potential hurdles, he is still optimistic. 

Thomas Hildebrandt (left) examines a rhino at Ol Pejeta Conservancy. Credit: Safari Park Dvur Kralove

Thomas Hildebrandt (left) examines a rhino at Ol Pejeta Conservancy. Credit: Safari Park Dvur Kralove

While Hildebrandt and Galli pursue these problems in Europe and Africa, half a world away, U.S. and Japanese scientists are working on a second, even ballsier plan. They hope to use recent stem cell technologies to turn tissue samples from deceased rhinos into egg and sperm cells, which they’ll combine to create healthy rhino embryos. If successful, the engineered calves would introduce vital genetic diversity into a population that otherwise would be limited solely to Najin and Fatu’s descendants. 

This part of the plan was made possible by the foresight of the San Diego Zoo, which began banking tissue samples in its “frozen zoo” back in the 1980s—including cryopreserved material from eight northern white rhinos. “We believe there’s enough genetic diversity in the individuals whose cells are preserved to constitute a new breeding population,” said Oliver Ryder, the zoo’s director of genetics. “We think that’s the only way to keep the northern white rhino from going extinct.”

Jeanne Loring, director of the Center for Regenerative Medicine at the Scripps Research Institute, is tasked with the sci fi-like feat of transforming the frozen zoo’s run-of-the-mill cells into induced pluripotent stem cells. Like biological blank canvases, those undifferentiated units can give rise to any type of cell in the body—a bit of biological wizardry that netted scientist Shinya Yamanaka the Nobel Prize in Physiology in 2012. While such technologies are usually pursued in the context of human reproduction and disease, in 2011, Loring and her colleagues used Yamanaka’s method to change some of Fatu’s skin cells into pluripotent stem cells. The idea now is to replicate that process for all of the frozen rhino individuals, and then turn those their stem cells into engineered egg and sperm cells.

“It’ll either be easy or hard or really hard,” Loring said. “No one’s ever tried this in an endangered species.” There are hints that it could work, however. In 2012, Katsuhiko Hayashi, a reproductive biologist now at Kyushu University, used gametes made from induced pluripotent stem cells to create healthy mice pups. Though rodents do not a rhino make, Hayashi has signed on to the northern white project, and Loring has high hopes.

Vágner often accused mankind of having “an unlimited faith” in technology’s “crude” power, while chronically overlooking the importance of nature. But technology may very well turn out to be the northern white rhino’s saving grace. More than that, though, the subspecies’ salvation hinges on the dedication of a team of men and women who are just as smitten with science and the natural world as Vágner was. Like him, they cannot abide the thought of standing by as the northern white rhino disappears forever.

“I personally think that if I have a solution to change a situation, then it is my responsibility as a scientist to do that,” Hildebrandt said. “My team and I feel a responsibility to try to save the biodiversity of our planet for the next generation.”

There has, however, been some backlash. Some fear that the audacious undertaking may signal that it’s acceptable to let species dwindle to just a few remaining individuals, because we can just use fancy science to save them. Others voice the opposite complaint, arguing that the whole thing is a wasteful lost cause. As Michael Knight, chair of the IUCN’s Rhino Specialist Group, told Nature News, “They should not be pushing this idea that they’re saving a species. If you want to save a [rhino] species, put your money into southern white conservation.”

Ryder pointed out, though, that San Diego Zoo donors who have backed the project specifically want to see the northern white rhino survive. Hildebrandt, on the other hand, gets no money for rhinos; his funds come from his institution, which invests solely in reproductive technologies. Likewise, Loring’s lab’s money goes toward stem cell research, not saving animals in Africa. “It’s not like there’s one pot of money you can spend around,” she said.

Practicalities aside, the researchers cite a moral imperative to act. “We can acquiesce and say, ‘Ok, too bad, there’s not much we can do,’” Ryder said. “Or we can say, ‘Is there something we can do?’ Even though we’re not 100 percent sure that we can do it, we think we have to try.”

The goal, Hildebrandt added, is for Fatu and Najin to see a northern white rhino calf before they die, which could mean as soon as 10 years from now. If that date proves overly aggressive, though, there is some wiggle room, he added: “Theoretical calculations say that a biological sample stored in liquid nitrogen can be sustained for 3,000 years before it’s destroyed by the earth’s natural radiation.”

Regardless of whether the project works out for the northern white rhino, the researchers steadfastly believe that the knowledge gained from their endeavors will benefit other species. The Javan rhino, for example, is down to just 60 individuals, while the Sumatran rhino hovers around 100. Through the techniques and technologies they pioneer, the rhino team may wind up saving even more rhino species.

As for what would Vágner think of all this, Stejskal at the Dvůr Králové Zoo preferred not to speculate. “That is something that is impossible to know,” he said. “I can say, though, that we are proud that we were able to give the northern white rhino more time on this planet.”


Author’s note: Sudan died in March 2018.

Najin and Fatu at Ol Pejeta Conservancy. Credit: Jan Stejskal

Najin and Fatu at Ol Pejeta Conservancy. Credit: Jan Stejskal


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Deacon, R., dir. (2017) Sudan: The Last of the White Rhino, BBC Natural History Documentary.

Hayashi, K., et. al. (2012) ‘Offspring from Oocytes Derived from in Vitro Primordial Germ Cell-like Cells in Mice’, Science 338: 971-975. 

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