Maybe it's his animal instinct telling him those weird-looking pandas are coming to grab him again. Or maybe he has an unusually well-developed sense of humour and thinks it is amusing to keep us standing around, looking stupid, on an icy mountainside. Either way, the baby giant panda is intent on being unco-operative.
Before we had even set foot in his enclosure, he gave his mother the slip and scrambled 10 metres up into the branches of a tree. There he sits, perched defiantly, apparently with no intention of coming down.
In a hidden cabin nearby, fitted out with a wall of television monitors positioned to capture every move of the panda cub and his mother, Cao Cao, I am left scratching and fidgeting with a veterinarian and a team of keepers, all unconvincingly disguised as pandas - the type that happen to walk on two legs and carry clipboards, medical bags and cameras. We are on standby to give the surly infant a medical check-up.
Last month, newspaper readers around the world were treated to photographs of Wolong Giant Panda Research and Conservation Centre keepers in comical panda suits cradling the baby panda. The shots - taken by one of the Sichuan centre's photographers - showed the panda, then four months old, being carried by staff wearing suits designed to ensure the infant doesn't grow accustomed to the sight and touch of people. One day, it could save him from poachers.
Now, on a snowy January morning in the mountains of southwest China, I am looking forward to being the first outsider to take part in a monthly health check. But the patient seems intent on break- ing his appointment.
'How long do baby pandas stay up trees before coming down?' I ask lamely, after half an hour of watching a TV monitor showing him rocking nonchalantly back and forth on his branch. The answer, I discover, is as long as he damn well likes - which, in this case, turns out to be 4? hours.
Finally, with the weak afternoon winter sun glist- ening on sticks of bamboo strewn enticingly on the ground below, the baby panda - which for a combination of superstitious and sponsorship reasons will not be named until shortly before he is released into the wild - deigns to shimmy his way to the ground.
This wilful, boisterous toddler could afford to make us wait. After all, he is no ordinary giant panda. He is panda royalty. Born to a mother bred in captivity but kept in a 2,400-square-metre outdoor enclosure since her pregnancy, he is the first captive giant panda to be raised in a natural setting with no 'sight' of humans.
When he reaches six months old, next month, he will move to a 40,000-square-metre enclosure filled with chickens, goats and pigs. Then, when he is two, he will take his first steps into the wild - and the expectations of the nation will be resting on his young haunches.
The hope is that this unwitting pioneer, a member of one of the world's most endangered species, with only an estimated 1,600 remaining in the wild and 300 in captivity, will be the first captive-bred panda to survive in the wild.
In 2007, the first attempt to release a panda bred in captivity ended in failure when Xiang Xiang, a five-year-old reared at Wolong, was found dead months after it had left the research centre, from injuries suffered in a suspected fight with wild pandas. After three years of training by staff at Wolong, the death was a bitter blow.
That's why no chances are being taken with this cub and why staff are going to extreme - some might say farcical - lengths to make sure he is tough enough to survive the rigours of the wild.
Huang Yan, vice-director for research at Wolong, explains how the uncomfortable suits came into being. 'This is the first time this has been done anywhere in the world,' he says proudly. 'We came up with the idea because captive pandas are too familiar with people. But by rearing them using the panda suits, the baby panda would grow up never seeing any people.
'If we didn't use these outfits, the baby would see humans and get used to them - and if he then saw people in the wild, they would seem familiar to him. We don't want that because maybe someone might harm him.
'We designed the panda suits ourselves then found someone who could make 10 suits for us.'
It might seem an extraordinary measure for the benefit of one animal but, as we are constantly reminded, there is nothing ordinary about this panda, whose life has been played out as if he were in an animal version of The Truman Show. The first months after his birth were particularly anxious. The baby was tiny, with no hair, and had to cope outdoors in rain and snow.
'The mother was very good throughout,' Huang says. 'She used her body to shield the baby and protected him from the wet and the cold.'
His progress since has been little short of remarkable. He's put on weight more quickly than Wolong's more coddled pandas - mothers rearing babies in the wild have more milk - and has never caught a cold or had any health problems. And, ominously for us, the baby panda started climbing trees unusually early.
'He started doing it in December and his mother was very worried about him and tried to stop him,' Huang says. 'A captive panda wouldn't start until two or three months later.'
On cue, Huang switches on a monitor, rewinds a tape and shows us a video dated December 20, when the baby panda climbed its first tree, fighting off his mother's frantic attempts to pull him back down. She eventually grapples hold of him and sends him tumbling two metres to the ground below in what looks like a bruising but memorable lesson in the dangers of ignoring a mother's advice. Dazed and surprised, he quickly returns to his feet and stumbles off in temporary defeat.
Whatever lessons the baby panda learned that day, resisting the urge to climb trees was not one of them.
When he eventually returns to earth on the day of our visit, one fearsome obstacle remains in the way of our entry to the enclosure: the baby's overbearing and demonstrably overprotective 111kg mother.
'If she thinks you are going after her baby, she will kill you,' Huang says. 'Adult pandas are very large and very strong. They will scratch and bite and they will attack if they think they are at risk.'
I cower behind the monitors in the cabin as two of the braver men in panda suits venture into the enclosure - one to pick up the baby panda, the other to distract the mother with handfuls of freshly cut bamboo.
'You can go now,' Huang says.
Struggling to peer through the eye sockets in my mask, I stumble out into the enclosure. As I reach the circle of upright pandas holding a bewildered-looking baby, I slip on something soft and almost end up on my black-and-white backside. The floor is littered with large green dollops of droppings.
'It's from Cao Cao,' one of the keepers explains afterwards. 'We collected it in a bag and dropped it in that area to give the smell of the mother and soothe the baby while he's being examined.'
Surprisingly, the panda poo does the trick. Considering he is being manhandled by three people in bad fancy-dress outfits, the infant is a picture of serenity. As the veterinarian and keepers prod and poke, he glances shyly around, his eyes rolling endearingly. At one stage, he bashfully puts an arm across his eyes as I gaze down at him, making it hard not to feel paternal.
Looks, though, are deceiving where pandas are concerned. Huang gave me strict instructions not to get closer than two metres from the panda: 'He mustn't be exposed to any more human contact than absolutely necessary. Even at five months, he can be quite aggressive and will bite and scratch - and it will hurt.'
The cub is weighed and has his teeth and eyes examined. Then he is subjected to a five-minute session of tummy massaging - which he seems to enjoy - in an attempt to produce his own droppings. The massaging is futile. He clearly isn't comfortable enough in our company to do what comes naturally to bears when they are in the woods.
My suit, designed for a more slender frame, is bursting at the neck and seriously short in the leg, leaving my boots exposed. The veterinarian and keepers conducting the medical checks have had to slip their hands out of their suits to work. And clipboards, test tubes and monitors are hardly what you might expect in a natural setting. Worse, perhaps, a keeper with a video camera cheerfully films the proceedings with his panda head completely off, so he can better capture the action in front of him. There's a nightmare in that, surely?
With his examination complete and a maternal outburst averted by a fresh serving of bamboo, the baby panda is at last placed gently on the ground - and immediately scurries to his mother.
As we shuffle out of the enclosure, I wonder whether the monthly ordeal will produce psychological scars. How would a human child cope with being wrenched from its mother by a group of bears wearing pink suits and masks, with clumps of fur sticking out at the ankles and hands?
'It was like watching an episode of the Teletubbies,' giggles an interpreter, who watched the whole thing on a monitor.
Marc Brody, founder and president of the Panda Mountain conservation group, which is working with the Wolong centre to prepare wild habitats for pandas, is a diplomatic man.
'It is an extremely simple idea and for that, it is just brilliant,' he says of the suit plan, before conceding: 'Animals smell you long before you see them. Clearly the proportions aren't right and the panda probably knows something is wrong by the smell.
'The good thing about the suit is it challenges us to think like a panda. You see the world through the panda's eyes. You become that young panda. You think, 'It's a big world out there. What do I need to survive?'
'At the same time, the idea of no contact between pandas and people whatsoever is probably taking the equation too far. In this world of roads and noise and human interaction, it's improbable that pandas are not going to have any contact with humans and be unaware of the encroaching human population.'
However surreal the experiment, though, its objective of preventing the infant from seeing human faces close up has been achieved thus far - and he is in the rudest of health.
'He weighs 10.4kg,' Huang says. 'That is very good indeed. And he is showing signs of aggression, which is what he will need when he is in the wild. He doesn't like to be with people and that is good.'
The scientists hope to release three to five giant pandas into the wild over the next five to 10 years, to help build up threatened populations across China. They also want to change the methods of husbandry for captive giant pandas, the aim being that all captive pandas will be born and raised outdoors.
Ironically, it was a natural disaster that created the conditions for the baby panda to be reared out of sight of humans. Thousands of visitors used to flock to the centre every year, to see scores of pandas being reared in captivity. That was until May 12, 2008, when a huge earthquake tore through the mountains of Sichuan, killing nearly 70,000 people and two of Wolong's pandas. Much of the centre was destroyed.
Nearly three years after the quake, the epicentre of which was just 30 kilometres from the centre, the facility remains in a state of disrepair and almost cut off from the outside world. All but four of the pandas - Cao Cao and three other females, which were erroneously thought to be pregnant - were moved to a new home, 160 kilometres away, and the research centre - once a hive of activity entertaining busloads of tourists, who stayed in a 'panda hotel' at its entrance - resembles the set of a post-apocalyptic movie. Its rusting gates are padlocked and old science labs stand deserted, their windows having been smashed by boulders.
Huang and his team of 16 keepers and research assistants live in the shell of the old hotel, where electricity wires and bare light bulbs hang precari- ously from the ceiling. The desolation becomes the centre's great allure with time, according to one of the keepers, a woman in her 20s from eastern Qingdao city, Shandong province, who was drawn to work at the centre by her love for animals.
'At first it's quiet and lonely but after a while you come to think and live just like a panda,' she says. 'You fall in love with the nature and the solitude. You become happy just with your own company, like the giant pandas.'
For now, with his mother never far from his side and his every move monitored by closed-circuit TV - and a team of panda-suited scientists visiting every month for the first 18 of his life - the existence of the baby panda in Wolong is secure.
All too soon, however, Huang knows the day will come when the young panda will venture out on his own into a hostile, threatening world. Like any loving father, he seems reluctant for that day to come.
'When the two years are up, we will seek the advice of international experts to see if they think he is ready for the wild,' he says. 'We're doing everything we can to make sure he's ready for what is out there.'