As flights go, it has to be the most memorable I have ever made. I checked in at Heathrow, waved goodbye to my suitcase and was hugely relieved when the stewardess noticed my heavily pregnant belly and thoughtfully bumped me up to first class. With ankles as swollen as mine, there was, after all, little chance of slotting them into an economy-sized footwell. At the time, I was working as a reporter for the journal Nature, and was travelling to Berlin to attend the 2004 European Society of Human Reproduction and Embryology conference. My remit was to find out what was going on in the world of assisted reproduction, stem cells and the like, and then write it up as news stories for the magazine’s website. But 7 miles (39,000 feet) up, I started to become acutely aware of the person sitting next to me. He had seemed normal enough when I squeezed past him to sit down – middle-aged, well-dressed, clean-shaven – but now he sat silently staring straight ahead, clutching a robust silver briefcase to his chest.
‘Can I put that in the overhead locker for you?’ asked a passing stewardess.
‘No thank you,’ replied the gentleman, tightening his grip. ‘I like to keep it with me.’
What, I wondered, could be so precious that he couldn’t be parted from it? What cargo, hidden inside the hand luggage, could be so important or fragile he cradled it like a mother holding a newborn? Was it some priceless family heirloom, a delicate antique vase, or could it be something more sinister … a handgun or maybe a bomb?
The clinking of the drinks trolley disturbed me from my thoughts. I accepted a small miniature bottle of vodka, then noting that my neighbour had clocked my obviously expectant frame, began to babble. I had no plans to drink the alcohol, I told him. I had only accepted it because it was free and you have to accept free stuff on aeroplanes. That’s why there’s a cupboard in my living room that contains 87 sick bags. We started chatting. He was, he explained in a gentle Irish lilt, a medic and a researcher also on his way to the same meeting, where he was hoping to attract attention to his work.
‘What work is that?’ I asked nonchalantly.
He smiled and glanced at his briefcase. ‘I can show you if you like,’ he answered without a hint of mischief. Then he laid the case flat on his lap and carefully flipped the latches. As he lifted the lid I could see that the inside was padded with a thick layer of black foam, and there in the middle, in a specially moulded depression, was what I can only describe as ‘an object’.
‘The object’ was roughly the same length and thickness as a family-sized bottle of fizzy drink. It was silver and smooth, fashioned from some sort of bright, shiny metal. Rounded at one end, it had wires dangling from the other. He picked it up carefully and turned the hefty curio round in his fingers. Then he leaned towards me and placed it in my hands. ‘Do you have any idea what this is?’ he asked.
I’d like to think that, at that moment I came up with either the right answer or a witty, memorable reply. In hindsight, I can tell you that ‘the object’ looked like a piece of modern art or an enormous bullet. It could have been a dibber for an over-sized sapling or a huge metal cigar for an enormous metal robot. But I’m not very good on the spot. Instead, I just looked dumbfounded and said ‘Err … dunno.’
What he said next has to be one of the most remarkable sentences ever uttered by anyone in the whole of the history of life on Earth.
A Piece of Cake
Round about the same time, 200 miles (350 km) away, a young rhino called Fatu was celebrating her fourth birthday. At the Dvur Kralove Zoo in the Czech Republic, the birthday girl was chowing down on a specially prepared cake made of watermelon, apples, carrots and grass. Almost full-grown, weighing as much as a family-sized car, her hair-fringed ears twitched back and forth with delight as she tucked into her birthday treat. Next to her, her mother, Najin, and her aunt, Nabire, selflessly ensured not a morsel went to waste. And then, with the cake finally demolished, the rhinos went back to doing what rhinos do best: kicking back in the mud.
It was a time of bittersweet optimism. In the wild, Fatu’s kind had been all but exterminated, while in captivity, less than a dozen remained. Hopes were high that in a couple of years, when Fatu reached sexual maturity, she would breed with one of the few remaining males and help boost the numbers of one of the most endangered species on Earth: the northern white rhino (Ceratotherium simum cottoni). Little did the birthday girl know, but heavy expectations had already been placed on her broad and muscular shoulders.
The northern white rhino is a magnificent beast. Built like a Russian tank, its thick, leathery hide hangs in folds over its large and powerful frame. It’s not, as its name suggests, white, but rather a very subtle and beautiful shade of grey. It’s the sort of colour paint manufacturers would call ‘Shrew Whiskers’ or ‘Obelisk Grey’ then charge you an arm and a leg to buy one small, watery tin. The word ‘white’ is thought to be a mistranslation of the Afrikaan’s word ‘weit’, which means ‘wide’, and refers to the animal’s square-shaped muzzle. Dark eyes twinkle on either side of its long, wizened face and it has two curved horns on the end of its snout.
When it was first discovered, in 1907, the northern white rhino was common in parts of East and Central Africa. It roamed the savannas of Chad, Sudan, Uganda, the Central African Republic and what is now the Democratic Republic of Congo (DRC), where it used its uniquely shaped muzzle to mow the grass. But then people took a shine to its rather impressive horns and started to hunt it for so-called ‘sport’. Commercial poaching set in. Little by little, relentlessly, the animal was exterminated from most of its range. But worse was to come. In the fifties and sixties, civil war broke out in Sudan and the DRC, and decades of lawlessness followed. In a world turned upside down by violence, it was impossible to keep the animals safe. The rhinos were slaughtered for their meat and for their horns, which in turn were exchanged for cash and weapons. First they disappeared from the Central African Republic, then from Sudan. In 2003, the year before Fatu’s fourth birthday, just 15 northern white rhinos were estimated to remain in their final stronghold, the Garamba National Park in the DRC. A plan was hatched to transport some of the animals to safety in Kenya, but the local media branded the act ‘a theft of national heritage’ and politicians blocked the move. A few years later all of the wild northern white rhinos were dead.
Today, rhinos everywhere are in danger. There are five different species. Asia has the greater one-horned,1 the Javan and the Sumatran rhino, while Africa has the black rhino and the white rhino, which can be subdivided further into northern and southern varieties. Three of the five different species are now critically endangered, and a staggering 95 per cent of the world’s entire rhino population has been lost in just the past 40 years.
Dvur Kralove Zoo started importing and breeding different types of rhino in the seventies when it was clear that their future was precarious, and since then has found itself heavily involved in rhino conservation. In 1975, they imported six northern whites from Sudan. ‘People realised that if the rhinos stayed where they were, it was just a matter of time before they would be killed by poachers,’ says Jan Stejskal, Director of Communication and International Projects at Dvur Kralove. So Fatu’s father, grandfather and four females made the 2,500 mile journey from the scorching banks of the Upper Nile to the more temperate Czech Republic. Two more animals were imported from elsewhere, and a little while later the not-so-tiny pitter-patter of rhino feet could be heard. Over the next two decades, four healthy northern white rhino calves were born, including Fatu’s mother, Najin, and later Fatu herself.
But some rhino species, it seems, are harder to breed in captivity than others. The zoo, for example, has produced more than 40 baby black rhinos, but after Fatu, the northern white rhino calves stopped coming. No one knows why. The keepers tried everything: hormone therapy, a change in diet, different lighting. They even built a new animal house. Southern white rhinos were introduced into the northern whites’ enclosure in the hope the two varieties might at least interbreed, but it was all to no avail. If the northern whites were unable to reproduce naturally then perhaps, the experts at Dvur Kralove reasoned, something else would have to be done.
The ‘Object’
Back on the aeroplane, I turned the weighty ‘object’ over in my hands. It was silver, shiny and smooth, and I found myself stroking it with my fingers, wondering what the hell it was.
‘Go on then,’ I said, ‘put me out of my misery. Tell me what it is.’
But nothing could have prepared me for what the man next to me said. It was a combination of words I never expected could go together: a sentence, I am sure, I will never hear again.
‘Well,’ he said without a hint of the bombshell he was about to drop, ‘I insert this up the rectum of rhinoceroses to make them ejaculate.’
Have you ever had one of those moments where time stands still? Where you are literally lost for words?
At this point in the story, I can tell you that one of three things happened. Can you guess which? Did I:
1. Shriek, ‘What? You’re telling me this thing’s been up a rhino’s arse?’ so loudly that the passengers in adjacent rows asked to move seats?
2. Drop said ‘object’ on the floor from whence it rolled noisily all the way from first class down to the back of second, taking out an elderly lady who was on her way to the toilet?
3. Say ‘how interesting’, then politely hand the object back and surreptitiously sanitise my hands with the complementary vodka I was unable to drink?
Answer: I’m British. Of course, it was option 3. My neighbour, it turned out, was Dr Stephen Seager from the National Rehabilitation Hospital in Washington, DC, a man who has spent a large part of his career inserting probes up the rectums of not just rhinos, but of other animals, too.
Men who have suffered spinal cord trauma, or who have other illnesses, can sometimes struggle to achieve an erection and ejaculate. This can rob them of the ability to have children, but electro-ejaculation, to give it its proper term, can help. A probe of the appropriate dimensions is guided up the rectum and an electric current is then used to stimulate the nerves around the prostate gland, triggering ejaculation. The sperm can then be used for artificial insemination or in vitro fertilisation, or it can be frozen away and used at a later date. When I finally tracked Seager down, 12 years after our original encounter, he had only the faintest recollection of the incident. After all, he told me kindly, he does a lot of flying and frequently travels with his electro-ejaculator, but he was keen to talk to me about one of his proudest achievements.
Teenage cancer is a terrible thing. ‘Six years ago,’ he tells me, ‘95 per cent of boys in this age group diagnosed with cancer would have died. Now 95 per cent survive, but the chemo- and radio-therapy leave them sterile for life.’ So Seager has adapted the electro-ejaculation technique so that it can be used on boys of this age. He collects semen samples from teenagers while they are being operated on for their cancer and, in so doing, offers them the chance to start a family later in life. Since he first started practising electro-ejaculation over 15 years ago, more than 100,000 babies have been born as a result of this technology. But it doesn’t stop there.
Modified versions of these probes are now commonly used in animal husbandry. Remember that turkey you ate on Thanksgiving or Christmas Day? Chances are it was conceived via electro-ejaculation and artificial insemination. In the world of conservation, the technique has been used to produce offspring in a number of at-risk species including Przewalski’s horse (Equus ferus przewalskii), the white-naped crane (Grus vipio) and the magellanic penguin (Spheniscus magellanicus). But there are two species for which the procedure has had a particularly profound effect. Most of the giant pandas (Ailuropoda melanoleuca) born in captivity have been produced via electro-ejaculation and artificial insemination, and the black-footed ferret’s recent recovery from near extinction is in no small part due to the same technique (see Chapter 8). In his time, Seager has collected semen samples from leopards, tigers and polar bears, but when I met him in 2004, he was en route not just to the conference, but to Berlin Zoo to discuss how assisted reproduction might help their captive breeding programmes. ‘I was worried that if I’d checked the briefcase into the hold, it might have got lost,’ he tells me. ‘Nowadays, of course, with all the extra security, I have to check my equipment into the hold. If I tried to take it on as hand luggage, I’d probably get arrested straight away. And then if I told them what the equipment was for they’d probably look at me and arrest me even more quickly.’
In the years that followed, Seager diversified and became more involved in the human side of things, while Berlin-based scientists have established themselves as world leaders in the field of large-mammal assisted reproduction. Veterinarian Thomas Hildebrandt and his team from the Leibniz Institute for Zoo and Wildlife Research (IZW) have spent the best part of two decades developing, refining and testing the equipment and procedures needed to help various animals, including rhinos and elephants, to reproduce artificially. A driven researcher and passionate defender of wildlife, he approaches his work with a scientific mind, tweaking a never-ending list of variables to improve the chances that the animals in his care will have offspring. Where possible he has patented his inventions, and he spends his days flying around the globe, visiting zoos and nature reserves, trying to change the fate of some of the world’s most endangered species. So when Dvur Kralove’s northern white rhinos stopped having babies, it was Hildebrandt that they called.
A Long Time Coming
I was intrigued to find out how the ‘object’ I encountered on my fateful British Airways flight is actually put to use. How exactly do you go about collecting semen samples from a two-tonne male rhino? So I too gave Hildebrandt a call.
Thomas Hildebrandt is a busy man, but very generous with his time. He speaks with a strong German accent, and proves to be candid, friendly and matter of fact. He explains to me how the probe he uses today is quite different from the one I would have seen on the aeroplane. ‘It’s a new concept,’ he says. In the early days, the probe wasn’t very reliable and sometimes caused damage to the animal, so Hildebrandt and his team reinvented it. The new version, based on their cumulative experience and encyclopaedic knowledge of the animals’ internal anatomy, uses a lower voltage and is a slightly different shape. It’s an altogether kinder, more efficient affair. It causes the animals no harm and it works every time.
Before it is used, however, the team must anaesthetise the animal and perform an ultrasound examination of its internal organs. It’s a procedure they pioneered and have performed on more than 1,000 rhinos, so they know exactly what they are doing. Wearing surgical scrubs and shoulder-length gloves, Hildebrandt carefully guides a long, bendy laparoscope deep into the animal’s rectum, then uses the ultrasound probe at its tip to look around. The black and white image is relayed to a nearby laptop screen, and thanks to a modified software program, reveals fine levels of anatomical detail. ‘We know all the normal and abnormal structures that can be found in all five rhino species,’ he says, ‘and we can check for these.’ The whole process takes less than 10 minutes, and only if the rhino is deemed fit and healthy do the team progress to the next stage.
After flushing out any urine and faeces from the rhino’s bladder and rectum, it’s time for the electro-ejaculator. The robust, cylindrical probe has been deliberately designed without a handle. It means that Hildebrandt has to plunge both the probe and the full length of his arm deep where the sun doesn’t shine, but it helps him to make sure that the instrument ends up in exactly the right spot, near the top end of the urethra, close to the prostate. Then he nods to a colleague who flicks a switch and delivers a few short pulses of electricity to the device. ‘Each pulse is no more than 15 volts,’ he tells me, ‘you can barely feel it on your tongue.’ It’s an image that makes me wrinkle my nose. With his arm and the ‘object’ still buried deep inside the rhino, Hildebrandt can’t feel the pulses directly but he can sense the muscular contractions that they trigger. The animal begins to ejaculate but the intrusive intervention isn’t over yet. In the wild, males need a lot of stimulation to get things moving. A male rhino’s penis is flanked by a pair of wing-like flaps that unfold inside the female and help keep the duo locked in a tryst, which can last up to two hours before the male ejaculates up to six times. Electrical stimulation brings the animal close … but no cigar. Meaning that to finish the job, one of Hildebrandt’s team must take matters into their own hands, literally. A colleague is called to ‘assist’ the animal, deliberately and vigorously massaging the penis so that when the animal does ejaculate the freshly released fluid can be guided along the pipework and into a collection tube. Each dose of ejaculate is around an espresso cup’s worth of semen, but it contains millions of sperm; millions of chances for new life to be created. From start to finish, the entire ordeal takes no longer than an hour and when it is done, the rhino is roused from its anaesthesia and left to get on with the rest of its day.
It’s a procedure that Hildebrandt performs around 40 times a year on different animals, including elephants, tigers and pandas. At the turn of the millennium, shortly after Fatu was born, he visited Dvur Kralove and collected and froze semen samples from two of the resident males. Then in 2006 and 2007, he returned and used the sperm to inseminate both Fatu and her mother, Najin.
Around this time, there was a flurry of good news. The first rhino ever to be conceived through semen collection and artificial insemination was born, not in the Czech Republic but in Hungary, at the Budapest Zoo. Then a year later another little rhino was born, this time produced with sperm that had been collected then frozen for three years before use. Here was proof that the artificial insemination procedures, so carefully honed by Hildebrandt and his team, really did work. And although both the newborns were southern rather than northern white rhinos, their arrival raised hopes that the technique would work in other rhinos, too.
Back in the Czech Republic, scientists waited patiently to see if either Fatu or Najin had become pregnant, but with the passing of time it became clear the inseminations had failed. The disappointing truth is that in most species tested so far, semen collection and artificial insemination fails more often than it succeeds. ‘There is an impressive list of mammals for which artificial insemination has worked at some point,’ says reproductive biologist William Holt from the Zoological Society of London, ‘but the number of species for which this is now a routine method is extremely small.’ Sometimes in rhinos, the technique begins to work – the inseminated sperm fertilises an egg creating an embryo, which then begins to divide. But then, for reasons unknown, division stops and the embryo becomes re-absorbed by the mother. What is known with certainty is that the longer female rhinos go without calving, the more difficult it becomes for them to get pregnant. It’s a frustrating Catch 22. Without regular pregnancies, northern white females develop cysts in their wombs, which then make it even harder for them to conceive. That makes the fact that Hildebrandt has managed to create a total of seven baby rhinos through artificial insemination an impressive feat. ‘It’s an incredible achievement,’ says the man from the plane, Stephen Seager. ‘It’s not easy to get semen from a rhino, it’s not easy to inseminate a rhino and it’s not easy to end up with rhino pregnancies.’ But sadly none of these rhinos are northern whites.
Last Chance to Survive
When it became apparent that Najin and Fatu hadn’t conceived, their keepers at Dvur Kralove were faced with a difficult decision. The rhinos could stay at the zoo and the IZW team could keep trying, or they could send their beloved rhinos somewhere else in the hope it would get their procreative juices flowing. ‘It wasn’t an easy choice,’ says Stejskal. ‘We had to do what was best for them.’
In the end, the zoo decided to send their last four fertile northern whites to Africa. Two females, Fatu and Najin, and two males, Sudan (Fatu’s grandfather) and Suni, would be relocated under the banner of the ‘Last Chance to Survive’ project. In an ideal world, the animals would have been returned to Sudan or Chad or one of the countries where they used to live, but the world isn’t ideal. It’s certainly not safe for rhinos. In Africa, the rhino’s main threat isn’t habitat loss, but organised gangs of criminals who operate across borders. Their foot soldiers use high-tech equipment to locate the rhinos in the vast open grasslands, then tranquilise them, hack off their horns and let them bleed to death. Demand comes from Asia and the Middle East where rhino horn is carved to make ornamental daggers and ground down to make medicine. It is used to treat everything from gout to cancer, snakebites to demonic possession, but the irony is, of course, that it does no such thing. Rhino horn is made from keratin, the same substance that forms hair and fingernails, and has zero medicinal value. Retailing at over £41,000 (US$60,000) per kilo on the black market, it is more valuable than gold, diamonds or cocaine, making it the most expensive snake oil in the world.
With no safe havens left in the animals’ former range, the decision was taken to send the Dvur Kralove rhinos to a maximum-security wildlife park in Kenya. The Ol Pejeta nature conservancy is 90,000 acres of rich, rolling savanna. A three-hour drive from Nairobi, it’s nestled between the foothills of the Aberdares Mountains and Mount Kenya. It’s home to all of Africa’s ‘Big Five’: rhinos, elephants, lions, leopards and buffalo, which makes it attractive both to tourists and poachers. So its enormous electrified perimeter fence is patrolled round the clock by armed guards.
It seemed their best bet. And so, one cold, snowy morning shortly before Christmas 2009, the quartet were lured into crates and driven under police escort to Prague-Ruzyne airport, where they were loaded onto a jumbo jet bound for Nairobi. Twenty-six hours after their journey began the animals were unloaded under the blistering sun, apparently none the worse for wear, and took their first tentative steps on African soil.
Because the animals were so precious – the last four fertile animals of their kind – they were given extra layers of security. Their pen, or ‘boma’, was in the centre of the park, surrounded by an additional electrified fence, dotted with watchtowers and patrolled by dogs. Their horns were filed down and fitted with radio transmitters, to make them less desirable to poachers and easier to track. And they were given their own personal bodyguards to protect them round the clock. For Sudan, the only one of the animals to be born in the wild, it was a momentous return to the continent of his birth. For all of them, it was the start of an entirely new chapter in their lives.
The hope was that the natural surroundings would turn their thoughts to love and a few years later, romance did appear to be blossoming. Suni was seen mating with Najin, but as time wore on, it became clear that Najin had not become pregnant. So the keepers came up with another strategy. They arranged a ‘blind date’ between the northern white rhino females and a southern white rhino bull. It was a sensible idea. Back in the seventies, a hybrid calf that was half southern white, half northern white was born at Dvur Kralove. If Fatu or her mother became pregnant by a southern white rhino bull, then any resulting progeny would also be a hybrid. It might not be a genetically pure northern white, but at least the northern white rhinos’ DNA would be preserved, albeit in a slightly diluted form. However the disappointment continued. There were no baby rhinos. To make matters worse, Suni was found dead in his enclosure in October 2014, apparently from natural causes. He was 34 years old.
At the end of that same year, Hildebrandt and his team visited Ol Pejeta to examine the remaining three animals, but what came next was an even more devastating blow. Sudan, they found, is too old and too weak to father children. His testicles have degenerated with age. Najin, his daughter, has problems with her hind legs and is unable to bear the weight of a pregnancy. Fatu, her daughter, has problems with her uterus. To top it all, genetic tests had previously revealed that both Sudan and Najin carried a genetic abnormality that could potentially interfere with their ability to reproduce. ‘Our assessment was that neither of the females was capable of becoming pregnant anymore,’ says veterinarian Robert Hermes, who works with Hildebrandt and examined the animals. ‘We think the pathology that we found is not treatable.’
Dead Rhino Walking
The northern white rhino is not extinct … yet. But it’s only a matter of time. Today, the only northern white rhinos left alive anywhere on the planet are the three animals, Fatu, Najin and Sudan, that still live at Ol Pejeta. There is no possible way the animals can breed themselves out of trouble. They’re too old, too ill and too related. Conservationists talk about species that have entered an ‘extinction vortex’, a downward spiral towards extinction from which they cannot naturally recover. That’s where the northern white rhino is right now. It is ‘functionally extinct’. Although a few stragglers remain, to all intents and purposes, the species has already gone. Fatu, Najin and Sudan are ghosts. They are the walking dead, a living embodiment of how human greed and carelessness is stripping species from the face of our planet.
The Ol Pejeta conservancy, the northern white rhinos’ carers, and Hildebrandt and his team are now faced with an incredibly daunting task. How to save a subspecies that has just three infertile members left? And how to silence critics who tell them there is no point?
Rhinos are important, not just because they are big and beautiful, iconic and mesmerising, but because they help create and sculpt the landscape they live in. Like the passenger pigeon and woolly mammoth before them, rhinos are ecosystem engineers. White rhinos fashion and manicure the grasslands of the African savanna. Their box-shaped muzzles are perfect for close-cropping the grass they feed on, leading to the creation of lush, fertile ‘grazing lawns’ that other species like impala and wildebeest depend on. It’s particularly important in high rainfall areas where the grasses grow taller and need more mowing. The rhinos’ grazing helps create a patchy savanna that has both areas of long, non-grazed grass and short, nibbled lawn. This is important when the fires come. Every few years, fire rips across the savanna, but where there are rhinos, the grazing lawns they create act as natural firebreaks. As a result, the fires are smaller, more diffuse and return less frequently. Rhinos change the behaviour of fire.
Studies of the last Ice Age show us what happens when all the big grazers go. When the megaherbivores disappeared from Australia, mixed rainforest turned to scrubby bush. When they went from North America, the lush mammoth steppe was replaced by mossy tundra. There were cascading effects that trickled all the way from the top of the ecosystem right down to the bottom. If we lose the megaherbivores that we have today, we run the risk of creating an empty, barren landscape.
But there’s more to it than that. Towards the end of the last Ice Age the world began to warm. It wasn’t like a thermostat being turned up gradually; it was more like someone flicking a gas fire on and off repeatedly. Temperatures fluctuated. The ice sheets began to melt. Yet for a time at least, the plant and animal life remained more or less the same. It was only when the megafauna went extinct that the ecosystem began to change fundamentally. Paleoecologist Jacquelyn Gill from the University of Maine has studied this period of upheaval in great detail, and thinks the megaherbivores helped buffer against the effects of climate change. ‘Modern and palaeontological studies suggest that when native large herbivores exist at sustainable levels, the ecosystems that they live in are more resistant to climate change and have greater levels of biodiversity,’ says Gill. Now fast forward 12,000 years to the present day. Our climate is changing. The world is warming. If Gill is right, then the presence of rhinos and other big herbivores could help to enhance biodiversity and make ecosystems more resilient to this change. But they can’t do it if they’ve all gone.
The northern white rhino is an animal that is still alive but that is in desperate need of de-extinction. When we think about de-extinction we are drawn instinctively to the species that are no longer with us, but there are species still alive whose future is so bleak that from a functional perspective, they might as well be gone. The Yangtze giant softshell turtle (Rafetus swinhoei), for example, is in a similar predicament. The largest freshwater turtle in the world, it was once common in parts of Southeast Asia, but just like the rhino, it was poached for use in Chinese medicine and its numbers have plummeted. Now there are just three of the snouted giants left: one in a protected lake in Vietnam and a pair at the Suzhou Zoo in China. They’ve laid eggs from time to time but none have been viable, and although artificial insemination has been trialled, it too has failed.
It makes sense to broaden our scope and include these species under the remit of de-extinction. From a practical point of view, de-extinction becomes more difficult the longer a species has been gone; ecosystems change and living relatives become more scarce. To choose an animal that is still alive – but almost beyond hope – makes perfect sense. With living members still present, we can study their biology and ecology, and amass the knowledge needed to de-extinct them while they are still here, rather than stabbing in the dark when they are gone.
If we don’t intervene, it’s inevitable that the northern white rhino will go extinct. Yet opinions are divided over what should happen next. Some think we should, in the words of the world’s most annoying song, ‘let it go’, that it’s already too late to do anything. But there are examples of species that have been sucked into an extinction vortex and made it out the other side. These vortices are not always the black holes they are painted to be, and with human ingenuity and science helping to pull a species back from the void, we massively increase the chances that a species will recover. Others argue that saving the northern white rhino is a distraction. Cash earmarked for conservation, they say, would be better spent on animals that can actually breed. ‘We’ve spent money on the northern white rhino in the past,’ says Susie Ellis, Executive Director of the International Rhino Foundation, ‘but it’s not our institutional focus anymore.’ Some suggest that because the northern white rhino has a close living relative, the southern white rhino – which is ‘only’ listed as Near Threatened by the IUCN – it doesn’t matter if the northern white rhino goes extinct. However, it does matter. It matters very much. People have argued for a long time about the relatedness of the northern and southern white forms. Some consider them separate ‘subspecies’, a blurry term lacking precise definition that tends to denote related animals that are genetically similar but geographically separate.2 As such, they argue, the northern white rhino is not genetically distinct enough to be worthy of rescue. But a recent study that scrutinised the DNA of the two varieties found that they are as different from each other as they are from the black rhino.
We should de-extinct the northern white rhino because it is genetically distinct and ecologically valuable. A keystone species, it represents ‘value for money’ through the repercussions its presence has on its landscape and on the species with which it interacts. If we let the northern white rhino slip away because there are other rhinos still alive that look ‘a bit like it’, then what’s to say we won’t apply the same logic next time round … Let the Javan rhino go because it looks a ‘bit like’ the greater one-horned rhino. Let the Sumatran rhino go because it looks a ‘bit like’ the black rhino. Our big grazing herbivores are slipping away. Sixty per cent of them, including rhinos, elephants and gorillas, are at risk of extinction. It has to stop somewhere.
Nor should we be blasé about the fate of those rhinos that still occur in larger numbers. There may well be around 20,000 southern white rhinos and 5,000 black rhinos left in the wild, but recent years have seen record levels of poaching seriously reduce their populations. In 2015, poachers killed 1,315 rhinos in Africa, making it the deadliest year ever for the animal. Experts fear that soon, populations will reach a tipping point. The number of deaths will exceed the number of births, and after that, it doesn’t take a genius to work out what follows. According to Save the Rhino, it’s entirely possible that all of the world’s rhinos will be extinct in the wild by 2026.
How Do You Like Your Eggs?
How to save the northern white rhino when its future seems so hopeless? In 2015, social media was briefly awash with photos of Sudan surrounded by his armed posse. The pictures were as beautiful as they were poignant. Against a wide African savanna and an expansive blue sky, a huge, imposing Sudan stood proudly in profile. All around him, as straight as pillars, stood his sentries clad in khaki, wearing military boots, clutching rifles. They stared towards the horizon, eyes on constant lookout for the first sign of trouble, while Sudan gently bowed his head. For a short time, because social media is fickle and transitory, Sudan became an internet sensation, the most famous rhino on the planet.
The media was keen to point out Sudan’s poignant claim to fame, that of being the only living male northern white rhino left on Earth. The fate of an entire species, they said, rested on his shoulders. But it’s not as straightforward as that. Already in his forties, Sudan is no spring chicken. He will die soon and when he does, he will be greatly missed. But the lack of his physical presence will have little bearing on the future of the northern white rhino. Thanks to Hildebrandt’s electro-ejaculator, semen samples from Sudan and several other males have already been collected and are now stored in cryo-banks waiting to be used. ‘Everyone thinks the crisis is the last male,’ says Richard Vigne, Chief Executive Officer at Ol Pejeta, ‘but we have lots of sperm stored. The bigger crisis is the lack of females and their eggs.’ Fatu and Najin, the last two female northern white rhinos on Earth, are the ones who really deserve the media spotlight.
Conservationists, cell biologists and other interested parties meet regularly to debate the best way to save the northern white rhino, and there are options. Unfortunately, every single one of them relies on being able to source and store northern white rhino eggs. For years this task was thought impossible. For a start, it can be very difficult to tell when a female northern white rhino is ovulating. Some rhinos – greater one-horned and Sumatran – ‘sing’ when they ovulate. They make peculiar vocalisations not heard at other times of the month. But white rhinos make no such fuss, and although male northern whites may be able to sense the hormonal changes that occur around ovulation, they are not obvious to our human senses. To physically ‘go in’ and retrieve an egg is also problematic. Not only is the female’s genital tract over a metre (3.3 feet) long, it is also, I am reliably informed, a ‘tortuous structure’, full of 90-degree turns and dead ends. This puts a female’s ovaries and eggs beyond the reach of all but the most specialist laparoscopic equipment. Then there’s the problem of storage. Unless an egg is to be used immediately, it needs to be preserved. But freezing is difficult because the large egg cells shatter, and other storage methods have also proved problematic. So for a while it was presumed almost impossible to store rhino eggs.
Thomas Hildebrandt and his team, however, have spent the last 15 years refining the techniques needed to overcome these problems. ‘My philosophy has been that we work step by step, optimising one procedure before moving on to the next,’ says Hildebrandt. The methods they have developed are a mix of high-tech interventions and, where possible, standing back to let nature run its course.
To tell when a female rhino is ovulating, Hildebrandt has enlisted the help of those who care for the rhinos the most: their keepers. At Ol Pejeta, Dvur Kralove and elsewhere, the keepers form very close bonds with the rhinos they tend. They don’t just feed them, wash them and muck them out. They talk to them softly, tickle them behind the ears and rub their bellies with a yard brush. In return, they have the rhinos’ trust and are able to monitor any physical changes that occur. Working with the keepers, Hildebrandt has discovered that one or two days before a white rhino ovulates, a plug of mucus is released from the vagina. It’s the animal’s way of having a bit of a clear out, sprucing things up and getting rid of any dead cells, so that the female is ready for sex. By recording when the discharge is released, Hildebrandt and the IZW team are able to calculate the length of each individual female’s menstrual cycle, and from that predict exactly when a female will next ovulate. It’s incredibly accurate – so much so, that the group use the strategy to pre-order their airline tickets.
When I track down Hildebrandt to talk about his work, he’s just back from the Czech Republic, where he has cracked the next step: collecting rhino eggs. With the rhino’s internal plumbing more convoluted than the plot of a Scandi-noir box set, Hildebrandt has devised an alternative route to reach the ovary. Under general anaesthesia,3 he guides a two-metre (6.6 feet) long, specially designed, patent-pending egg-retrieval device up the animal’s rectum, then punctures a hole through to the ovary on the other side. This enables him to aspirate and retrieve the eggs. It might sound crude, but with care, precision and an astute dose of antibiotics, the risk of infection and complications is minimised. Hildebrandt and co. recently used the method to harvest five eggs from a southern white rhino female at Dvur Kralove Zoo. The eggs, however, are not fully mature, so the next step is to bathe them in a carefully concocted mix of nutrients in a culture dish. It’s a delicate process that has been optimised by Cesare Galli and Giovanna Lazzari of Avantea, an Italian biotech company that is now collaborating with the IZW. Critically, it causes the eggs to ripen, and then and only then can they be either frozen or used to make a baby rhino.
Collaborating closely with Fatu and Najin’s keepers, the IZW team now plans to make twice-yearly trips to Ol Pejeta to collect eggs from the females for as long as they continue to make them. The menstrual cycle of a white rhino lasts between 30 and 35 days, so the animals have plenty of time to recover and cycle normally between visits. ‘We have everything in place,’ he says. The first tranche of eggs will be matured then frozen as an insurance policy, but after that, Hildebrandt will move into unchartered territory. Having tried and unfortunately failed to make northern white rhinos via artificial insemination, where semen is introduced directly into the female’s reproductive tract, the team will now try the next best option: to make a ‘test-tube rhino’ and transfer that back into a surrogate womb.
In 2015, they took a massive step towards this goal when Avantea scientists managed to harvest four eggs from the body of Fatu’s then recently deceased aunt, Nabire. Thinking it would give them the best chance of success, they decided to try fertilising the eggs with sperm from a southern white rhino and, much to their delight, managed to create one little IVF embryo. Although it stopped developing when it was still a tiny bundle of cells, the development buoyed the spirits of those trying to save the northern white. ‘This is the first time anyone has managed to fertilise a northern white rhino oocyte [egg] in a dish,’ says Hildebrandt. ‘It’s a big achievement.’ And he’s right. It might not be the northern white rhino calf he so desperately hopes for, but it’s the nature of cell biology research to proceed in small incremental steps. It would be welcome but entirely unrealistic to expect early attempts at rhino IVF to produce a live calf. In the meantime, however, while Hildebrandt and his collaborators continue to work methodically, polish their techniques and make the best of the limited resources they have, Fatu and Najin’s biological clocks are ticking.
The problem, explains team member Robert Hermes, is that the IZW team is having to refine its protocols with limited biological resources of variable quality. ‘If I worked with dairy cows,’ he says, ‘I could go to the abattoir and get 100 cattle … 200 ovaries … and then collect many hundreds of eggs.’ It would provide enough basic research material to try lots of different protocols and tease out what works best, for the cow at least. But rhino protocols need to be devised with rhino eggs and, like the rhinos they come from, those are in short supply. It’s for this reason that the team has been refining its protocols on less endangered rhino species such as the black and southern white rhino, but even then there are problems. Around 50 per cent of rhinos in captivity, the stock from which Hermes and Hildebrandt draw, have reproductive problems of some sort. So although they may still be releasing eggs, the quality of those eggs is uncertain. If only there was some other source of northern white rhino sperm and eggs …
The Y Factor
Many years ago, when I worked as a cell biologist in the laboratory at London’s Institute of Psychiatry, we laboured under two major misunderstandings; first, that regular, almost constant tea breaks would greatly improve scientific productivity, and second, that making stem cells was problematic. At the time, people were very excited about making stem cells because of their promise for medical research. But how to get hold of them? Back then, the only way to source genuine human stem cells was to take an IVF-created embryo, just a few days after conception when it was still a tiny ball of cells, and use a fine needle to aspirate the stem cells from it. But there were lots of people who found the idea unpalatable because the embryo was destroyed in the process. It didn’t matter that these were ‘surplus’ embryos never destined for the comfort of a mother’s womb; the pro-life lobby still hated it. ‘Making’ stem cells was not just difficult, it was ethically charged.
Then along came a man called Shinya Yamanaka from Japan’s Kyoto University, who not only solved the moral conundrum, but also came up with a way of making stem cells that was easy. He made them from skin cells, without the need for embryos at all. In 2006, Yamanaka took skin cells from an adult mouse, added a handful of genes and reprogrammed the DNA inside the skin cells into a stem cell-like state. The cells that he produced, which he called ‘induced pluripotent stem cells’, or ‘iPS’ cells for short, could then be coaxed to become other cell types, including nerve and heart cells, proving that his iPS cells behaved like stem cells. It was cellular alchemy; Nobel Prize-winning gold. Ian Wilmut, creator of Dolly the sheep, then at the MRC Centre for Regenerative Medicine in Edinburgh, described it as ‘one of the big experiments of the decade, maybe even the century.’ In no time at all, other laboratories began to adopt Yamanaka’s treatment. They added the same four genes – or ‘Yamanaka factors’, as they’ve become known – to adult cells and began to make their own iPS cells. And it wasn’t just mouse skin cells that could be given the iPS makeover. Scientists soon showed that iPS cells could be generated from the cells of different species, including rats, monkeys and humans. Meanwhile, elsewhere, in separate experiments, scientists have shown how stem cell-derived eggs and sperm can be used to create healthy, live mice. The studies raise the prospect that in the future, scientists might be able to take a skin cell, turn it into a stem cell, then use that cell to generate eggs and sperm to help generate test-tube babies for infertile couples. Intriguingly, it also raised the possibility that if this could be done for humans, it could be done for other species, too, including endangered ones.
It was something that stem cell researcher Jeanne Loring from the Scripps Institute in La Jolla, California, was thinking about when she was looking for an excuse to take the researchers in her laboratory on a day out. ‘I wanted to take them to the San Diego Zoo,’ she says. ‘It’s one of my favourite places, but we needed a reason to be there.’ So they decided to meet with Oliver Ryder, the Director of Genetics there, and discuss whether stem cells could somehow be used in wildlife conservation. To Loring, it was obvious. Skin or other cells collected from endangered animals could, in theory, be reprogrammed to become iPS cells, which could then be used to create eggs and sperm, which could then be used to make babies. Loring, who had decades of experience working with stem cells, had the knowhow, and Ryder had the raw material.
A little over 40 years ago, Ryder and colleagues began collecting skin samples from rare and endangered animals in the hope that one day, they might come in useful. Over the years, the collection, known as the Frozen Zoo, has grown into one of the biggest cell banks in the world.
Squirreled away in its many bubbling vats of liquid nitrogen are more than 70,000 samples from over 700 different species of mammals, birds, reptiles, amphibians and fish. The cells have been used in hundreds of scientific studies, helping researchers understand how species evolve and genetic variation changes over time. When the black-footed ferret had its genome sequenced, they used cells from the Frozen Zoo. Critically, for the future of Fatu and her kind, Ryder has been stockpiling cells from the northern white rhino, starting with a female called Lucy, whose cells were frozen in 1979. Since then, the Zoo has amassed a veritable ‘crash’ of northern white rhino cells, including samples from Fatu donated by the IZW team.4 Frozen in tiny vials are the cells of 12 different animals: eight unrelated individuals and four of their offspring. According to Ryder, that amounts to a significant sampling of genetic diversity and, if used wisely, should be enough to help save the subspecies from extinction. There is more of a gene pool preserved in these tiny tubes than survives in all of the remaining live animals put together.
A short while after their trip to the San Diego Zoo, one of Loring’s post-docs, Inbar Friedrich Ben-Nun, thawed some of Fatu’s cells and began to grow them in a dish. Adding a judicious dash of the seemingly magical ‘Y’ factors, the cells were turned into their more versatile stem cell state. Loring and her team had made the world’s first iPS cells from an endangered species, and the signs are that the cells are every bit as talented as the team had hoped. In a tissue culture setting, they can divide and be coaxed to become many different types of cell. The next step, says Loring, is to try to turn them into rhino eggs and sperm.
Researchers haven’t given up on the idea of using the eggs that are directly harvested from Najin or Fatu, rather they are aware that they need a Plan B. ‘We realise now that to save the northern white rhino, we are going to have to use some advanced cellular techniques, such as iPS cells,’ says Dvur Kralove Zoo’s Jan Stejskal. And with iPS cells come new options.
If fully functioning rhino sperm and rhino eggs can be made from iPS cells, they could be ‘married’ together in a dish and used to make embryos. With samples of their skin cells already in the Frozen Zoo, there’d be no need to subject Najin and Fatu to the twice-yearly egg collections, and Loring’s team now hope to make iPS cells from the other 11 northern white rhinos whose skin cells have been frozen. If the technology is reliable, it would offer researchers an almost limitless supply of northern white rhino eggs and sperm with which to optimise their methods, and would allow them to mix and match genomes of different animals at will, maximising that all important genetic diversity.
The resultant embryos would be nurtured in a dish for a few days then transferred to a surrogate’s womb. Because of their health problems, Fatu and Najin would not be used as surrogates. Instead the world’s next northern white rhino will be born to its cousin, the southern white. At Ol Pejeta, they have already earmarked four young, fertile females for the job. They live in a huge pasture, in large social groups; important, Hildebrandt believes, because natural behaviour and social interaction are key to keeping rhinos both happy and fertile. Before the embryo is implanted, the surrogate will be allowed one final fling with a sterilised bull rhino because it’s thought his sperm-free ejaculate will help make her uterus more receptive to the embryo. It will prime her body for pregnancy and hopefully give the embryo a better chance of survival. And while none of this has ever been attempted before, Hildebrandt remains unfazed. ‘We have successfully transferred embryos back in many other mammal species,’ he says. ‘The rhino reproductive tract may well be in a class of its own, but I am optimistic that we will master this step in the near future.’
Little by little, all the pieces of technology needed to save the northern white rhino are dropping into place, and iPS cells, so versatile and easy to make, could represent a game-changer for the fate of this larger-than-life iconic wonder. But it’s not just the northern white that could benefit from this technology.
Loring’s team has also made iPS cells from the drill (Mandrillus leucophaeus), a short-tailed mandrill-like monkey whose numbers have more than halved in the last 30 years. In Thailand, Anucha Sathanawongs at Chiang Mai University has made elephant iPS cells. The immediate goal is to devise therapies for the country’s ailing captive elephants, many of whom suffer from ulcers and arthritis, but Sathanawongs is also hoping to coax the elephant iPS cells into eggs and sperm. If the technique works and can be replicated elsewhere, it could provide a ready supply of eggs for those interested in bringing back the woolly mammoth, or an approximation of it. iPS cells have been made from the endangered snow leopard (Panthera uncia), from chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla) and orangutans (genus Pongo). The development of iPS cells means that repositories such as the Frozen Zoo are now more important than ever. They’re not just preserving the cells and genomes of the world’s wildlife, they are a starting point for new life, a vital repository of genetic diversity which, if used carefully, has the potential to revive not just individual animals, but entire, viable populations. We shouldn’t just be trying to save wildlife: where possible, we should be saving their cells, too.
Bring Back the King
When I first heard about de-extinction, I was intrigued but uncertain. I have since determined that I am fully in favour of scientists developing new techniques, not just to ease the pace of extinction, but to also reverse it. We need to proceed cautiously. We need to ensure these options are safe, effective and have public buy-in, but they offer a vast amount of potential that deserves at least to be explored. I’ve realised that if we are to bring a creature back from the past then we had best choose one that we know a lot about, one whose reproductive physiology is known, whose cells we can manipulate. It had best be an animal that we love, that we have space for, that we miss and we mourn. It should be a creature whose ecology is well known, a keystone species whose return would have a positive ecological impact. It should be an animal that warms the cockles, that could inspire future generations to look after their planet and prevent future extinctions from happening.
Everyone has heard about the current biodiversity crisis. We all know that flora and fauna are in trouble, but because the vast majority of species are going extinct quietly, invisibly, in places hidden from our everyday lives, it’s all too easy to become sucked into the misguided belief that extinction is not happening on our watch. Species used to go extinct in the past, species will go extinct in the future, but today, as I sit in my centrally heated home, sipping my coffee, scanning the internet, nothing has changed. In the time it has taken you to read this chapter, another species has disappeared. In the time it’s taken me to write this book, at least 20,000 species have gone extinct, but save for the odd one that makes the official IUCN Red List most of them are completely unknown. We live in the midst of the sixth mass extinction, but it’s largely invisible or ignored.
When I first started thinking about de-extinction, I asked myself which single creature would I most like to see brought back from extinction? In the real world, of course, we’re not restricted in this way. I may not have chosen the woolly mammoth or the gastric-brooding frog or the passenger pigeon to top my list, but I wish the researchers working to bring them back the very best of British. There are good, sound reasons for bringing these particular creatures back. When the first healthy de-extinct animal is born, it will be a truly incredible achievement. I look forward to that day. But if I had to choose just one …?
As I write these final pages, I realise I have arrived at an answer that I never expected. The animal I would most like to bring back from extinction is one that is still alive … just. Because of our greed and our lack of respect for nature, the northern white rhino is nearly gone. Sudan, the last male standing, is entering his twilight years. One eye is clouded by cataracts. When he’s around other rhinos, they bully him. It makes him lose condition, so his carers at Ol Pejeta have created a new enclosure just for him. Fatu and Najin live next door and although he is unable to see them, he can smell them and knows they are there. ‘To create a northern white rhino before the last one disappears is the driving force for me,’ says Hildebrandt. Fatu, the youngest of the three, may well be that last animal. ‘We hope that Fatu at least will get to meet a new member of her own kind,’ he says. The only thing that can save the northern white rhino now is science. If I had to choose just one animal to de-extinct, then the wrinkly-faced, twinkly-eyed northern white rhino would be it.
We are responsible for the downfall of the northern white rhino, but with assisted reproduction, stem cell science and genome editing, we have at our fingertips some of the most powerful technology on the planet. It’s a science that can save species, shape evolution and sculpt the future of life on Earth. We are so close to being able to use these methods to make facsimiles of species that are long gone, to enhance the genomes of animals that are still with us and offer a lifeline to species that are on the brink. It’s up to us to decide how we use this knowledge. I believe it was Spiderman’s great uncle, the late, great Uncle Ben, who summed it up best when he turned to his web-spinning nephew and said, ‘Remember, with great power comes great responsibility.’
As I write this line, there are just three northern white rhinos left alive on the planet. By the time you read it, they might all be gone.
NOTES
1 Which has the marvellous scientific name Rhinoceros unicornis.
2 The northern white is Ceratotherium simum cottoni while the southern white Ceratotherium simum simum.
3 The rhino, not Hildebrandt.
4 A ‘crash’ is the collective noun for rhinos. Other African animal collectives include a leap of leopards, a cackle of hyenas and my favourite, a dazzle of zebras.