Zhang and Bexell had put together a book about a panda called Jing Jing, documenting her first year. 'There is very little quality publishing about pandas,' says Lusby. 'Which is surprising because every kid loves pandas.'

The idea of a educational book about the animals aimed at children was welcomed by Lusby's bosses, especially when they discovered that Jing Jing was to be the model for one of the fuwas, the Beijing Olympic Games mascots, which were chosen to represent endangered species.

The mournful image of Jing Jing chosen for the book's cover proved to have universal appeal and Watch Me Grow, Panda has been flying off the shelves in the United States, Britain and Australia.

Readers are presented with a series of powerful images taken from when Jing Jing was barely the length of a pencil through to when she was a playful cub, able to climb trees, play with other bears and pose, diva-like, for tourists.

'The success of the book was driven by kids loving it, it wasn't that Penguin pushed it harder than anything else,' says Lusby. 'One of the things with pandas is that they are so anthropomorphic. They look like people; the way they act, the way they move. Even adult pandas do not lose that cute factor, with those black circles around their eyes.

'If you look at them sitting eating their bamboo they look like a fat guy with a big bowl of popcorn. That is why panda diplomacy is so successful - they are very expensive to keep but the places that get pandas really embrace them and they become the star attraction very quickly.'

Bexell's book turned into an unlikely hit for Dorling Kindersley, a Penguin Group publisher specialising in illustrated reference books, notching up sales of 100,000 copies in the first three months, rising to 140,000 by the end of last year. This is an exceptional achievement for a children's educational book and, with all profits going to the Chengdu centre, it is also helping to secure a better future for the mainland's pandas.

Last year, the Sichuan earthquake laid waste to some of the pandas' habitat, killing an unknown number, wiping out their bamboo supplies and severely damaging Chengdu's sister research centre at Wolong. The central government believes 1,600 giant pandas remain in the wild but some experts say that figure is on the high side.

Bexell is one of them. The American-born scientist has devoted her professional life to panda research and has lived and worked in Chengdu for the past decade.

The publication of Watch Me Grow, Panda has been a double blessing; generating funds for research and raising awareness of just how grave the plight of giant pandas has become.

'The earthquake devastated the area where pandas live,' says Bexell. 'The land there was just swept away into the valleys. Female pandas nest in hollowed-out old trees or rock crevices and most of them have gone. If you take away the pandas' nesting places, you take away the hope of reproduction.'

Experts believe extinction is a real possibility.

'Parts of Sichuan and Gansu are included in the top biodiversity hotspots on the planet but they also have some of the highest human impact [on the environment],' says Bexell. 'Pandas need the land. The breeding programme could be our hedge against extinction. If the wild habitat vanishes, this is our last hope.'

Bexell boils with indignation when listing the intrusions by man into the panda's habitat. Only when asked about the particular animals under her care does her tone soften; even serious scientists can't help but become emotionally attached to pandas.

'Jing Jing is very personable and playful, she doesn't have any fears like some pandas do,' says Bexell. 'She has a very confident mother, Ya Ya, who brought her up well and prepared her for what the future holds. Jing Jing is amicable and curious and very brave, a well-rounded animal who gets on well with others.

'One of my favourites is Da Shan, she has a twin brother. I like her a lot - she is very prissy and concerned about her appearance. She is always combing her own fur and is fastidious. There was an incident a couple of years ago that made me cry. She had a cub born that didn't [survive]. The keepers kept her lactating, as they needed the milk. One of them gave her a toy panda and she started taking care of it - licking it and holding it and carrying it like her own cub.'

Along with the centre's other residents, Jing Jing and Da Shan will spend their lives in captivity but any cubs they have could be set free to roam the mountains of Sichuan. While putting pandas back into their natural habitat is a long-term goal of the centre, the focus during the past decade has been on building up the numbers of those bred in captivity: the current headcount is 82.

After Zhang introduced a diet with fewer sup-plemental foods, such as eggs and milk, there was a surge in the animals' birth rate but the exact conditions that induce pandas to flirt, court, cuddle and, ultimately, reproduce remain a mystery.

'One of our latest theories is that in the wild males have to compete for a sexually active female,' says Bexell. 'When the female goes into her breeding mode the males congregate around her. It's a bit like a pretty girl in a bar - all the guys have to fight for her attention. They duke it out to see who gets the girl and she then gets to go home with him.'

The Chengdu zoologists are experimenting with a breeding programme that reintroduces the competitive element.

'We have created an environment where the males can see each other and hear each other and smell each other - and that leads to stimulation and mating begins,' says Bexell. 'Nobody has published any research on this yet because it's still at the experimental stage. But it could answer questions about why pandas have been reluctant to mate in captivity. The theory holds that in the wild, females go for the most aggressive, creative, confident and assertive male.'

Funding such research requires donations, which is why the Penguin windfall was such a bonus, especially as entry fees from visitors, the centre's main source of income, virtually dried up in the months after the Sichuan earthquake. Exactly how the money from Watch me grow, Panda will be spent has yet to be decided but a portion of it is likely to go towards more advanced training for local staff, possibly overseas, and on the long-term goal of educating China's next generation on the need for conservation.

'There have been big changes in the last five or 10 years but more education is required,' says Bexell. 'The biggest issue is the drain on wildlife that is plaguing China. There is an urgent need for conservation. I think this upcoming generation really cares about animals and attitudes will change. You have to change behaviour and instil a conservation ethic. People have to understand where clean food comes from, where clean water comes from, where clean air comes from.'

They must also be aware that destroying the forests and rivers where pandas roam will, inevitably, lead to the extinction of the species.

Bamboo, the main source of nutrition for pandas, is now in short supply due to the earthquake, rapacious land development and the general thoughtlessness of humans.

'Things like disposable bamboo chopsticks drive me crazy,' says Bexell. 'Bamboo is scarce and it is our responsibility to make sure there is enough for the pandas. If only people thought more. For example, don't eat wild mushrooms or bamboo shoots and think carefully about what Chinese medicine you are using, what it contains and where it came from.'

Visitors to the Chengdu centre, which has the world's largest population of pandas in captivity, are very welcome.

'It is the best day out you can have in China and only 30 yuan (HK$34),' says Bexell. 'It is a real treasure of Chengdu.'