At about 5pm on 25 March, a cold, wet Wednesday earlier this year, Tian Tian, the female giant panda at Edinburgh zoo, stirred from the wooden platform in her outdoor enclosure and began to bleat. Tian Tian, who was born in Beijing zoo in 2003, has proved a terrific hit with visitors since she arrived in Britain with the zoo’s male panda, Yang Guang, in December 2011. Yang Guang, whose name means “Sunshine”, might be a larger and, to all appearances, more affable creature, but Tian Tian (“Sweetie”) is a panda with more edge, more wit and more dash.
These are unusual qualities. Pandas are vegetarian bears with slow metabolisms. They subsist almost entirely on bamboo, which they digest poorly. They do everything they can to avoid unnecessary exertion. If you give Yang Guang a ball, he will most likely see if he can eat it, then let it go. Tian Tian, on the other hand, has been known to skip after balls and do forward rolls. Sometimes she hangs from the bars on the top of her indoor den – a pose that her handlers call “ninja panda” – just for the hell of it. She is not all nice. Tian Tian has bullied keepers off the job, and sometimes takes sly swipes with her enormous claws at passing vets. “She has got her own mind, most definitely,” said Alison Maclean, the chief panda keeper at Edinburgh zoo, who seems to love her deeply for precisely this reason. “You have to be very, very careful around her.”
That afternoon, as they prepared to leave for the day, the panda team at the zoo was watching Tian Tian especially closely. When she stood up and wandered over to a pale green grate that separates her enclosure from Yang Guang’s, Maclean, who was sitting in her office a few hundred yards away, followed her on one of 16 cameras that monitor the bears day and night. Late March is right in the middle of the short, fragile and confusing period that is the panda breeding season. Female pandas ovulate just once a year. The optimum window for them to mate – “the drop zone” in zoo parlance – is about 24 hours long. Depending on the vagaries of climate, diet and bear, the build-up to this moment can be conspicuous and last for weeks, or it can arrive suddenly, with no warning at all. “The signs can be very subtle,” Simon Girling, Edinburgh zoo’s head vet, told me. “We are always worried that we are going to miss the window.”
On the screen, Maclean watched Tian Tian approach the grate and continue her calls. Having evolved to lead solitary lives, pandas are kept in separate enclosures in zoos, to prevent them from killing one another. The only exception to this is the breeding season, when the bears are invited to communicate and are ultimately, according to the euphemism, “introduced”. Seeing Tian Tian through the bars, Yang Guang, who had spent the afternoon sitting on top of a cave, eating, called back. “We thought, this was quite good,” said Maclean, “quite interactive, quite nice.”
Maclean was cautious, though. Since the pandas’ arrival, the team at Edinburgh zoo had already tried three times to breed the bears – with considerable fanfare and public attention – and each attempt had ended in disappointment. After a thoroughgoing review of these attempts in late 2014, this year’s season carried with it a sense of added pressure. But the keepers had also come up with one or two new tricks. A few weeks earlier, Maclean had daubed urine from Long Hui, an impressive male panda kept at Schönbrunn zoo, in Vienna, all over Yang Guang and Tian Tian’s enclosures, in order to spice the air with competition and possibility. “She spent a lot of time sniffing and seeing what was going on,” said Maclean. “He came out and was just like, ‘Whoa!’ He was all over the place.”
As in previous years, however, most of the keepers’ match-making work took the form of minute monitoring – of bamboo consumption, behaviour, daily photographs of Tian Tian’s vulva – to ensure everyone was primed for the big moment. An important part of this surveillance is the analysis of hormones in Tian Tian’s urine. From mid-March onwards, Maclean and her team try to collect up to four samples a day, but this is a challenge. Females coming into heat have evolved to pee in ponds and streams, to alert potential mates, and although Tian Tian has been trained to urinate on command, she frequently refuses to comply. “Quite often she is like, ‘I’m holding on to this,’” said Maclean. Keepers scurry in with syringes to collect precious drops from the ground when she is not looking.
The urine samples go by bus or taxi to Forbes Howie, an endocrinologist at Edinburgh University, but their ultimate interpretation is the domain of Iain Valentine, the director of the panda project at Edinburgh zoo. A tall, toothy, loping man, Valentine is Edinburgh’s maverick and its schemer, the person who first dreamed of bringing pandas to Scotland – the most northerly place the animals have ever been known to live – about a decade ago. Since then, he has been both evangelist and architect of the zoo’s efforts to produce the UK’s first-ever panda cub. Every spring, Valentine, who is 51 and an expert on the capercaillie, a large woodland grouse, spends weeks puzzling over fluctuating levels of panda oestrogen and progesterone, as well as various other proteins, looking for telltale signs of impending ovulation – “double peaks” and “big falls” – and hankering for the next set of results from the lab.
By the afternoon of 25 March, Valentine was convinced that Tian Tian had reached “crossover” – a threshold when her oestrogen levels overtake those of progesterone – 12 days earlier, and that she was due to ovulate in two or three days’ time. A measure of warning is vital. Because the pandas are so rare, and the opportunities to breed them are so fleeting, it is standard practice in zoos to artificially inseminate females, as well as to attempt to mate them naturally. For scientific back-up and political cover (all pandas are officially on loan from the Chinese government), Valentine already had two experts from the CCRCGP – China’s main panda research facility – installed in the Holiday Inn next door to the zoo, and he had a team of reproductive biologists from Germany booked on flights the following day to prepare for the artificial insemination. The Germans, led by Prof Thomas Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research, had artificially inseminated Tian Tian in the two previous years.
Valentine watched Tian Tian through the cameras. In a urine sample taken that morning at 8.30am, he had noted a small decrease in her oestrogen, but thought little of it. The team took a second sample at 9.50am, but decided not to send it, and to wait instead for those results to come in with the afternoon sample, which was taken at 2.30pm. “We thought nothing much was going to happen,” said Valentine. With no new data expected until later in the evening, and quietly encouraged by the images of Tian Tian and Yang Guang bleating through the grate, the panda team went home.
* * *
Valentine lives in Newburgh, a village on the banks of the river Tay, about an hour north of the zoo. He was preparing supper when he received an excited message from Howie, the endocrinologist, at 7.08pm. “Results up,” it said. “Yinks!” The tests showed that Tian Tian’s oestrogen levels had dropped suddenly in the short interval between her two samples that morning. She had almost certainly ovulated, and that was now nearly 12 hours ago. Tian Tian was well into the drop zone. “Sneaky minx,” Valentine texted back. The clock was ticking, and his mind began to race with decisions and difficulties – all the people he had to phone and bring together. “The Chinese are in the Holiday Inn. The vets are at home. The keepers are at home,” he told himself. “The Berlin team is in Berlin.”
The first person he called was Zhaoyuan Li, a Chinese field biologist based in Scotland who has acted as the zoo’s interpreter and liaison with Chinese scientists and bureaucrats since 2008. Li was in the hotel with the two Chinese scientists, and Valentine wanted their take on the test results. Then he rang Girling, the head vet. Maclean got a call from one of her keepers while she was in the supermarket. She put her shopping back on the shelves and ran out to her car. The Germans tried to change their flights.
The first captive-bred giant panda, Ming Ming, was born in Beijing zoo on 9 September 1963. The first successful artificial insemination was carried out in 1978. Even so, almost 40 years later, breeding pandas in zoos remains a business of conflicting opinions, uncooperative bears, and near-hysterical levels of public and press interest, and occasional disaster. (At London zoo in the early 1990s, keepers had to spray their bears with fire extinguishers after one bit the other during an introduction. In 2010, Xing Xing, a 14-year-old male on loan to Japan, died after a routine electro-ejaculation.) Only a handful of zoos outside China have managed it successfully. The key decision facing Valentine and the team that night was whether they had to attempt an artificial insemination, or even natural mating, in the next few hours – or if they could safely wait until the following day. Valentine knew that American teams often wait more than 24 hours after ovulation before inseminating pandas, but in Europe, the rule of thumb is to do it as soon as possible. The pandas were not giving any clues. Logging in to the cameras from home, Maclean saw that Yang Guang was sound asleep.
Girling, the vet, lives a short distance away from Valentine, and the two men decided to drive to Edinburgh to meet the Chinese vets. Before they left, they told the rest of the team to assemble at the zoo. During the drive, Girling and Valentine were apprehensive. They became increasingly convinced that they should inseminate Tian Tian that night. It was too risky to attempt a natural introduction, in case Tian Tian got injured, and it did not look as if the Germans could get there quickly enough. “If we were going to do this, we were going to have to do it ourselves,” Girling said. By the time they reached the Holiday Inn, at about 10.30pm, the Chinese experts had arrived at the same conclusion.
The team – keepers, vets and the zoo’s head of animals, Darren McGarry – gathered in a room at the animal collections department towards midnight. There were about a dozen people. Almost all of them had been involved in the previous inseminations of Tian Tian and had been preparing for this moment for several months. There were not enough people for both bears to be sedated (most zoos prefer to use fresh semen, which they coax from the sedated male panda using an anal probe) so Girling, who had not inseminated a panda before, would use a frozen sample from February 2014. The vet took a gas-powered pistol loaded with anaesthetic and walked down the hill to the enclosure.
Maclean was with Tian Tian when she went under. “The last person she sees when she goes off to sleep is me,” she said. The night was cold. It took four people to lift the panda on to a stretcher, and then on to a set of hay bales that acted as an operating table. A heated blanket kept her warm. Next door, in a small kitchen, Valentine and the Chinese scientists defrosted straws of Yang Guang’s semen and examined them under a microscope. The only delay came when there was a slight disagreement – exacerbated by translation problems – over whether Tian Tian should be inseminated in her vagina or her uterus.
In the end, Girling injected two catheter-fulls of Yang Guang’s semen directly into her womb. Tian Tian woke up alone in her cage, with Maclean on the other side of the bars. At around 5am, Girling and Valentine got in the car to drive home. The adrenaline of the night had given way to fatigue. Girling was relieved, but Valentine remained unsettled. He has described producing a cub as “the icing on the cake” for Edinburgh’s panda project, but in truth it is much more than that.
A baby panda in Scotland would be proof of the bears’ wellbeing, a measurable contribution to the saving of the giant panda and the biggest event in the zoo’s 116-year history. It would also be an immense personal validation of Valentine’s work as a scientist and a conservationist. And that night, the insemination of Tian Tian had the feel of a rushed job. “This was the first year where, if I am being honest, I had a question mark,” he told me. In the dark Scottish dawn, it began to snow.
***
Pandas are the oldest extant bear. A set of fossilised cheek teeth found in southern China in the 1980s suggests that the species diverged from the main Ursus family around 7m years ago. They used to roam across east Asia: panda fossils have been found as far north as Beijing and as far south as Burma. It was probably climatic changes, and the advance of humankind, that drove the bears, with their unusual sixth digit (the panda thumb) and piebald markings, into the steep and inaccessible mountains of south-west China.
There they embarked on one of biology’s great love stories: of carnivore and plant. Lots of things about pandas – their genes and digestive systems, for example – suggest that they should eat meat, but instead they have a diet that is 99% bamboo. Indeed, the relationship of pandas and their chosen food source is the framing device of almost all scientific research into the animal (sample paper: “Giant Panda Bear Genome Unveiled: Bamboo Diet May Be Linked to Inability to Taste Savouries”), a kind of meta-narrative for the overall particularity of the bears and their long survival.
That is because – to the casual observer, at least – bamboo and pandas appear to be in a marriage of profound inconvenience. In the wild, bears eat for up to 13 hours a day, digesting about 17% of what they consume, compared to, say, 80% for a grass-eating deer. Owing to their low-calorie diet, pandas are unable to build up sufficient fat reserves to hibernate and have smaller brains, smaller kidneys and smaller babies than other mammals their size. Surviving – just about – on bamboo is both the evolutionary genius of pandas and the limiting factor of their existence. George Schaller, a pioneering biologist who tracked giant pandas for five years in Sichuan during the 1980s, describes eating the plant each day as their “one great vision in life”.
Foraging alone, and sleeping when they are not eating, wild pandas seldom come into contact with humans. In the canon of Chinese history, art and folklore, they make only tiny and fragmentary appearances. The Classics of Seas and Mountains, a work of geography written some time between 770 and 256BC, speaks of the mo, “a bearlike, black and white animal that eats copper and iron”. (Pandas were most often encountered by herb-diggers in mountain camps who would find their cooking pots chewed out of shape.) From then on, the bears occurred under such a variety of names – around 20, including meng shi shou (beast of prey), bai bao (white leopard) and shi tie shou (iron-eating beast) – and implausible descriptions that by the time western explorers and missionaries began turning up in China in the 19th century, they did not know whether the beast was real or not. When Ted and Kermit Roosevelt, sons of the US president, Theodore, became the first westerners to shoot a panda, in western Sichuan in April 1928, they said it was “like the animal of a dream”. When Ruth Harkness, a New York fashion designer, became the first foreigner to capture a live panda eight years later, she named it Su Lin, meaning “a little bit of something cute”.
Scientists generally agree that there are five main factors that make primates, birds, bats and carnivores candidates for extinction: large body size; small geographic range; slow life cycle; high position in the food chain; and low population density. Giant pandas possess four out of five of these liabilities, but they also have one almighty advantage in a human-ravaged world – a direct line into our tender hearts. When Chiang Kai-shek wanted to thank the American people for sending aid to China during the second world war in 1941, he despatched, in his words, two “comical, black and white, furry pandas” to the Bronx zoo.
No one seems truly able to explain the emotional appeal of pandas, except to say that it is massive, instant and near-universal. Sir Peter Scott knew what he was doing when he made a largely invisible bear the logo of the World Wildlife Fund in 1961. At Edinburgh zoo, Alison Maclean has watched hundreds of thousands of visitors come and sigh and sometimes blink away tears as they watch Tian Tian and Yang Guang slowly cavort in their dens. “The way they sit, the way they pick things up, and eat … People just have an instant connection with them,” she said, “because they can look like someone in a suit.”
* * *
Of course, in the larger scheme of things, our soft spot for pandas has not counted for much. Biologists believe there were once 100,000 pandas in Asia. By the time Schaller and the WWF were invited to China to study the animal in 1980, there were little more than 1,000. Pandas had been under official protection in China for decades, but it had not made the slightest difference. Poaching, deforestation and snares left out for deer and wild pigs had devastated the population. By 1985, after a bewildering bamboo die-off in Sichuan, during which hundreds of pandas starved to death, the icon of the global conservation movement, a survivor of ice ages, was about to disappear.
Zoologists around the world wondered how to get the numbers up. One possibility was by breeding the bears in captivity. The question was how. The only accounts of panda reproduction in western scientific literature were tantalising scenes from Schaller’s fieldwork. Crawling through bamboo thickets in the fog and snow, Schaller had watched complex mating rituals in which lone females climbed hemlock trees and moaned while four or five males paced and fought below, pushing each other off cliffs. “At 17.50, she descends,” Schaller wrote of one such encounter in 1981. “He mounts briefly four times in rapid succession. Both squeal, chirp and bleat, and the male pants.”
One of the myths that biologists are keenest to dispel is that pandas are bad at breeding. You don’t survive for 7m years without knowing a thing or two. It’s just that panda sex, like many other things about pandas, is not quite like anything else. There is the “fetalised” panda penis, with its unusually small and winged baculum (penis bone), which seems to place a certain emphasis on technique, and those short, passing hours when the females are ready to breed. The whole reproductive event is shrouded by the same energy shortage that defines panda lives. Cubs are born ludicrously small and immature, weighing around 100g – 000.1% of their mothers, or the size of a mouse. If a panda gives birth to twins, she will abandon one in a matter of days because she cannot look after both. Schaller concluded that successful mating in the wild rested on an intricate process of “synchronisation”, in which males and females subtly geed each other up, over the course of days if not weeks, through calling, scent-marking and other indecipherable means, until they were ready to take the plunge.
The difficulty has been in recreating those conditions in captivity. Schaller, who is now 82 and the vice-president of Panthera, a big cat conservation organisation, is among those who believes it is more or less impossible. “If you sit next to the same animal year after year,” he asked me, “where is the excitement?”
For a long time, international efforts to figure out the problem were chaotic and poorly coordinated. Western zoos poured millions of dollars into panda displays – pandas cost $1m a year to borrow from China – with scant thought for their conservation, while China’s domestic panda work was stultified by bureaucracy and paranoia. The absence of the bears from pre-communist iconography allowed them to emerge during the 1960s and 1970s as powerful and politically safe symbols of the new China. But the country’s zoos and panda reserves were short on funding and expertise. They were mortified when foreign biologists proved more successful at breeding pandas than they were. In 1991, vets at London zoo learned that their new female panda, Ming Ming, who had been sent to the UK ostensibly to breed, had already been artificially inseminated around a dozen times in China without success, and was almost certainly infertile. “We all knew: I knew. They knew. I think they knew we knew,” Jo Gipps, the zoo’s former director, told me.
Out of sheer desperation, things began to change. By the mid-1990s, there were 117 pandas living in captivity in China, a worrying proportion of them descendants of a single, libidinous male called Pan Pan. At a conference in Chengdu in December 1996, a group of international breeding specialists, together with around 50 Chinese scientists, agreed to overhaul the programme. A proper studbook, recording the genetic information of captive pandas, was introduced (Tian Tian is number 569, Yang Guang is 564) and every bear got a health check. Biologists swapped hunches and the breeding rate ticked up. In the 25 years between 1963 and 1989, 119 pandas were born in captivity, of which around one in three survived. In the decade that followed, 109 were born and 66 survived.
Since then, China’s captive population, which is mainly based in large breeding centres, where females have plenty of mates to choose from, has increased to 396 pandas – a level regarded as genetically safe from inbreeding. The wild population has enjoyed a similar, quiet recovery, although these animals remain trapped in their long, slow dance with extinction. Earlier this year, the latest quadrennial survey reported that a total of 1,864 pandas are living in around 30 fragmented populations in the forests of Sichuan, Shaanxi and Gansu. If they were people, you could fit them on a couple of tube trains.
* * *
Iain Valentine is an unguarded, hopeful soul. “I wouldn’t say I am a serious scientist,” he told me one morning in the old keeper’s bungalow at the zoo, where he has his office. “But I have an inquisitive brain, so I will puzzle something out or have a theory or an idea about something.” The thought of bringing pandas to Edinburgh first took hold in 2005. Valentine had just got hold of some koalas from San Diego zoo, which has one of the best panda-breeding records outside China, and he decided to ask their advice. “Of course they all fell about laughing,” he said, “because they realised that you are crazy if you start the journey.”
It took six years. Pandas in China are the preserve of the State Forestry Administration (which runs the reserves and breeding centres) and the Ministry of Construction (which runs the zoos). A few initiatives, such as the country’s reintroduction programme, in which captive pandas are trained to live in the wild – with the help of scientists in panda suits, smothered in urine and faeces – are run by both at the same time. Valentine sent emails and beseeched diplomats. He made fact-finding trips to Beijing. When China’s main panda breeding centre, in Wolong, was destroyed by the Sichuan earthquake in 2008 (one panda was killed), he had Edinburgh zoo send £15,000 and a set of satellite phones.
The years of waiting gave him time to devise his own plans. Valentine thought the bears would do well in the cold and wet Scottish climate, and that it wouldn’t be hard to grow bamboo for them to eat. To increase his chances of producing a cub, he decided to brook convention and ask for two adult pandas that had already bred – Tian Tian gave birth to twins in 2009 – rather than a sub-adult pair who would come into sexual maturity at the zoo. “I thought, ‘Hey hey, I’m off and running here,’” he told me. “I was wrong. I was wrong on lots of fronts.”
The deal to bring Tian Tian and Yang Guang to Edinburgh was signed on 10 January 2011, as part of a £2.6bn trade package between the UK and China that included an agreement to pursue deepwater drilling in the South China Sea. It came at an exceptionally turbulent time for the zoo. Poor summer weather in 2009 and 2010 and the impact of the recession had pushed the Royal Zoological Society of Scotland to the edge of financial collapse. The zoo was then hit by a series of scandals and fallings-out among its senior staff. (One manager was accused of stealing money intended for the chimpanzee enclosure). After Valentine and Maclean went to the Bifengxia panda reserve to meet Tian Tian and Yang Guang for the first time in March 2011, Valentine was suspended from his job for four months, briefly threatening the whole project. (He was subsequently reinstated to a post more narrowly focused on the pandas, and the deal got back on track.)
The arrival of the bears, however, swept the gloom away. They turned up on a FedEx truck on 4 December, and went on display 10 days later. During a typical December, Edinburgh zoo gets around 8,000 visitors. In the last two weeks of 2011, 56,000 people came to see Tian Tian and Yang Guang, and their popularity has proved surprisingly resilient ever since. Zoo economics says that you can expect a 70% bounce in visitor numbers in the first year of a panda loan, with the increase fading to 9% by year three, but the bears in Edinburgh have bucked the trend. Last year, the zoo’s numbers were still 25% up, three years in, and that has been without a cub to really pull in the hordes.
When I asked Valentine what a baby panda would mean for the zoo’s finances, he garbled his words in excitement. “The sky’s the rocket,” he said.
* * *
The Edinburgh team had its first shot in the spring of 2012, just a few months after the pandas arrived. By then, Maclean and Valentine had already realised that the bears were much more sensitive than they had previously thought. They hated the wind, and were easily spooked by noise. They spent most of their time in indoor viewing areas attached to their enclosures, rather than outside. Their keepers, meanwhile, got a crash course in bamboo. Yang Guang, in particular, has turned out to be something of a gourmand, discarding one species of the plant in favour of another, and switching between stalks and leaves, sometimes on a daily basis. (Maclean now serves the pandas 24 different species of bamboo, which are shipped in weekly from a plantation in the Netherlands). At the same time, Tian Tian began to show flashes of her mercurial personality. When Chinese keepers came to check on her, they surprised Maclean by calling her “Bad Panda”.
The first breeding season was more or less a trial run. In fact, it is the only time the pandas have ever been put together to mate. I watched footage of one of their introductions, and saw Yang Guang hoisting himself uncertainly in Tian Tian’s direction, while she squirmed under him and seemed to bark unhelpful instructions. “He’s a gentleman and maybe he shouldn’t be,” said Maclean. “Do you know what I mean?”
In 2013, a long winter and gale-force winds seemed to play havoc with Tian Tian’s hormones. “We thought she would never get to the point,” said Girling, the vet. Even a Chinese expert from Wolong was “a little bit flummoxed”, according to Valentine. Eventually, Tian Tian started sending contradictory signals to Yang Guang as well, calling him into her enclosure and then scaring him away. “Her behaviours just weren’t conducive,” said Valentine. Last year was a similar story: “He was interested in her, she was not interested in him.” Zookeepers do not like being drawn on questions of animal rapport, but there is obviously something missing between Edinburgh’s bears. “She is not seeing him,” Maclean explained, “as the big, butch male.”
The team has resorted to artificial inseminations, but in their way, these have only revealed new layers of mystery. Like other bears, female pandas experience embryonic diapause, which means that once a fertilised egg has become a blastocyst, it can float around in the uterus for months until the mother is in a prime state to embark on her pregnancy. Among energy-starved pandas, this wait can last a very long time. Gestation periods have been timed at anything between 83 days (a little short of three months) and 163 (closer to six). For unknown reasons, female pandas also often experience “pseudo-pregnancies”, generating all the symptoms – hormonal changes, nipple development, even the production of bright-green first-stage breast milk – just without the cub. They can also lose the foetus – re-assimilating it back into their tissue, a process known as “resorption” – at any point. “It blows your mind,” said Maclean. Ultrasounds rarely help, because panda foetuses are so small.
This means that summers at the zoo have taken on an aching, expectant quality, with keepers, vets and visiting Chinese experts often reduced to their own personal theories and coping strategies to survive the months of hope and doubt. “You can get befuddled with the numbers,” Maclean admitted. The press and the outside world do not help, getting revved up in the spring about panda sex and the “tunnel of love” – as the rarely used connecting passage between Tian Tian and Yang Guang’s den has been called by the Scottish papers – then bored in the summer and cynical by the autumn. Last year, Edinburgh even had to put up with sniping from San Diego zoo, where a spokeswoman cast doubt on Tian Tian’s reported pregnancy. Valentine insists that Tian Tian fell pregnant in both 2013 and 2014, only to resorb the foetus a few weeks later. He says she has the scars on her uterus wall to prove it.
The whole thing is a drama. And the sense of spectacle – the press releases, the inseminations, the fabulous cost (Edinburgh’s pandas cost up to £2m a year to run, about 20% of the zoo’s budget) – provokes questions about what exactly pandas in western zoos are meant to achieve. From a strict conservation point of view, everyone knows that shipping individual pairs of pandas across the world, to strange cities in strange climates, is a terrible way to make more of them. “How do we save giant pandas? Send them all back to China,” Gipps, the former director of London zoo, told me. “Put them into breeding situations where they can really make babies.”
Many wildlife campaigners even question the scale of China’s captive breeding programme, believing that now it has passed the point of ensuring genetic diversity, the emphasis should be on reintroducing the bears in large numbers to the wild. (Since 2006, just four pandas are known to have been released, of which two have died.) And then there is the equally problematic, but more subjective, issue of how the pandas feel about it all: after making it through the Miocene and Pleistocene eras, do they really want to stick around for a life of panda cams and anal probes? As Chris Packham, the BBC wildlife presenter, put it in 2009: “Let them go with a degree of dignity.”
When I put this to Valentine and Maclean, they rehearsed the familiar arguments for sending pandas abroad. The bears generate millions of dollars for important scientific research and conservation work in China. They are what campaigners call an “umbrella species” – a charismatic mammal saving the hides of tens of thousands of less lovable organisms in the bamboo forests of Sichuan. And there are still so few of them, the logic goes, that even a cub produced at vast expense in Scotland is still one more panda. (Maclean and the other keepers hope that any offspring of Tian Tian might one day grow up to enter China’s reintroduction programme). For people in the business of selling conservation to a paying public (a ticket to Edinburgh zoo costs £18), giving up on pandas would also mean giving up on the idea that people’s emotional response to the natural world matters at all. “If you can’t save the panda, then what can you save?” Valentine asked me. “Because I am going to find it really hard to get people interested in snails.”
After so many years of trying, though, these abstract arguments give way to more personal hopes. Spending time at the zoo this summer, I got the impression that the members of the the panda team at Edinburgh had each developed their own motives for wanting Tian Tian and Yang Guang to breed. One afternoon, Maclean and I stood talking about Tian Tian’s prickly personality. Her outdoor enclosure stood empty; she was taking a nap inside. Maclean wore a purple training whistle around her neck. “I don’t think I would ever stop trying,” she said. “I think it is very important that she has cubs. You know, it is the only time I would say she is going to be sociable with another panda – when she is with a youngster.”
Valentine, meanwhile, is a man with a riddle to crack. Once he described breeding pandas as a “biological moonshot”, and the entire enterprise – its complexity, its farcical notes – seems to give him great pleasure. In late July, as the rest of the zoo slipped into the now-familiar summer longueur of diapause and advanced panda semiotics (“As we like to say, ‘She has a bun in the oven, but the oven is not switched on yet,’” the panda presenters told the crowds every 10 minutes or so), Valentine buzzed around with graphs and theories. He dropped hints about a new battery of tests, monitoring Tian Tian’s prostaglandin metabolites, a compound that helps induce labour in humans, which he believed would help track the progress of panda pregnancies with more accuracy and certainty than ever before. Valentine described this work alternately as “classified” and “new science”. “You have to understand,” he said, “I’m a much more optimistic than a pessimistic person.”
The bears, of course, gave nothing away. One day I watched Yang Guang drink slowly from a dish of water, then transport himself with implausible grace from a wooden platform to a metal bed filled with hay, where he covered himself in bamboo, as if tipping a salad bowl on top of his head. Tian Tian, meanwhile, specialised in her own amusement. She has a habit of going into her indoor viewing area for a drink, waiting just long enough for the keepers to spot her on their cameras, and then slipping out of view as the crowds arrive. One morning, in a seemingly restless mood, she walked up and down along the glass wall of her outdoor enclosure, a display of strolling that quickly filled the stands with visitors. Tian Tian sat down in a pond and looked out at us. There was a long moment when the bear seemed to become mutually transfixed by a toddler in a blue coat who was wearing a set of reins. The panda stared at us. We stared back. “What is that?” the boy asked, finally, pointing at Tian Tian. “What is that?”
* * *
According to Valentine’s data, Tian Tian became pregnant during the second week of July. In recent years, scientists at Memphis zoo, in Tennessee, have developed a test involving ceruloplasmin, an enzyme produced in the liver, which they claim can distinguish between real and pseudo panda pregnancies. By early August, Valentine was confident that this reading tallied with Tian Tian’s other hormone data. He picked up a spike in her prostaglandin metabolites as well, another good sign. Tian Tian was also acting differently. She ate less and slept more. Her mammary glands grew. She began to spend more time in and around her cubbing box, a basket that her keepers had placed in her den and modified this year to include a heating element. She dragged in rotting logs, and scratched at the bark on the walls.
When I called to check in with the panda team on the afternoon of 12 August, Girling told me that Tian Tian was “just grand”. Valentine’s voice was thick with an elation I had not heard before. “She’ll give birth next week,” he said. “I am 90% certain it is going to happen.”
After years of trying, Valentine explained, everything was finally falling into place. The labs had used the new tests to analyse old urine samples collected from Tian Tian in 2013 and 2014, and Valentine was confident that he now understood what had gone wrong. The foetus in 2013, he explained, had only developed for a week before it was resorbed. In 2014, it was two and a half weeks. We were well past that stage now. “The numbers are very different this year. That is what we wanted,” he said. “I think we are over the hump.”
The keepers began a 24-hour watch of Tian Tian two days later, logging into the cameras from home and monitoring her in four-hour shifts. Because of gaps in her urine data, which made timings difficult to predict, Valentine forecast a four-day window for the birth, from August 18 to August 21. Maclean and her team competed for slots on the watch rota. For two years, her office has contained a fold-out hospital bed and intensive care baby incubator – in case Tian Tian gives birth to twins, and she has to rear one herself. The walls are covered with instructions on how to prepare puppy formula, which is used for baby pandas. Maclean unfolded the bed, and sterilised the room. On the afternoon of August 17, the zoo closed the panda enclosures and thanked visitors for their cooperation “during this exciting, but delicate period”.
Tian Tian withdrew into herself. Treated decorously by her keepers all year round, they gave her extra space, and fed her bamboo shoots. She kept her back turned, making it difficult to conduct even visual examinations. “We couldn’t get near her,” Maclean said. Sometimes the panda growled and barked. It became impossible to contemplate carrying out an ultrasound, which might reveal a glimpse of the cub, and even to collect urine samples, whose analysis Valentine hoped might give a 24-hour warning of the birth. On the night that the zoo closed the panda enclosures, he emailed: “We are flying blind and not sure what is going on.”
Relying on their observations of Tian Tian alone, the panda team were not sure how to interpret her behaviour. They had never seen her so intransigent before, but they had also never believed themselves to be so close to the birth of a cub. Valentine veered between worry and bursts of overwhelming excitement. “This is the first time ever,” he said. “This has never happened to us.”
Last Tuesday afternoon, Maclean noticed damp patches appearing on Tian Tian’s cubbing box. They came from under her tail. They were clear, vaginal secretions. The panda began to lick herself and the team prepared for her to give birth. “Iain was the level-headed one,” Maclean told me. “We were skipping around the section, trying not to grin from ear to ear.” But nothing came. Valentine, who does not have access to the cameras at home, went to bed and prayed for the phone to ring.
The same pattern repeated the following day. More secretions. More skipping. No cub. “We got to the point where we thought, ‘This is a bit strange,’” said Maclean. “But you let your heart rule your head.” On Thursday, Tian Tian dragged more logs into the cubbing box. The increasing agony of waiting in Edinburgh was interrupted by happy news from abroad: a successful ultrasound, followed by the birth of twins, at the Smithsonian zoo in Washington; Malaysia’s first ever panda cub, born in Kuala Lumpur.
When I spoke to Valentine last Friday morning, on the last day that Tian Tian was expected to give birth, he did his best to sound pleased about the other zoos. “Isn’t that wonderful?” he said. “It is great when other people do it.” But his voice was empty, and tired. “This is tough,” he said. “This is really hard. We’re grabbing on to the positive behaviours we see, but also we start to think, ‘Well shouldn’t we be seeing this by now?’” He hadn’t had a urine sample from Tian Tian for over a week. Valentine talked me through the scientific progress of another breeding season: from the insights gained by the prostaglandin work, he explained, he was close to a final, precise figure for the length of a panda pregnancy. But he was already wondering what on earth had gone wrong.
The following night, at around 10pm, Valentine emailed the rest of the panda team and told them they could stand down. For a fourth year in a row, there would be no cub. They had never come so close. “This has been another step,” he told me later. “But how many steps do we need? I don’t know.”
Yesterday the panda enclosure at Edinburgh zoo was closed. A black gate barred the entrance. Padlocks hung on the doors to the indoor viewing areas. At around lunchtime, I slipped inside with Valentine and Maclean. There was no wind, and the air smelled slightly of fish, from the penguin exhibit next door. “My husband was like, ‘Will a cuddle help?’” Maclean said. “I was like, ‘Nope. Step away.’ It’s sad. It’s hugely sad. I wanted it for her. But we will pick ourselves up and go again.”
Yang Guang was in his den. We fed him a couple of apples. When he stood on his hind legs, he came up to my shoulder. There was a small set of TV screens in the corner, and one of them showed Tian Tian in her own den next door. She was on her back, legs splayed, on top of her cubbing box. Earlier, Maclean had been in to see her, alone. When she turned on the lights, Tian Tian had covered her eyes with her paws. Now she lay in the gloom, staring up at the bars on the ceiling. It was her 12th birthday.
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