Any panda knows that, when climbing down, his feet should always lead the way - but Yong Liang, the Chinese claim, is the first hand-reared panda to survive without any of its mother's milk.
At Peking Zoo, where he was born, he spent those first five months only with humans, imitating their actions. Now he lives in a small room - but the door has to be locked because Yong Liang has learnt to undo the bolt and turn the handle. Down the corridor his twin brother, Yong Ming, who was raised naturally by their mother, lives in a cage.
Yong Liang's 'parent' figure is Liu Wei Xing, the zoo's chief panda expert. 'When we first introduced him to other pandas,' Mr Liu says, 'he was very afraid and ran to the keeper.' And although he now weighs 50kg, 'when he plays with the other young pandas, he always gets the worst of it. If he is scared, he is always soothed if a man comes in.'
Yong Liang was born in the autumn of 1992, as part of the zoo's artificial insemination breeding programme, and had to be taken from his mother when just seven minutes old. Pandas, which are notoriously hopeless mothers, often give birth to twins, and in the wild they will always abandon one.
Xu Juan Hua, deputy director of the zoo, explains that the mother panda takes her new- born cub in her paw to put it at her breast, and therefore she cannot cope with twins. Several breeding teams in China have managed to keep twins alive, but always by helping the mother to suckle them alternately.
Panda breeding in captivity, remains an inexact science; a panda can conceive on only a few days a year, and it is difficult to know which. A new-born panda is extraordinarily delicate, and normally would be suckled for six months; it weighs about 100g, and has no sense of sight, hearing or speech. 'The baby is more like a human foetus, it is so underdeveloped,' says Ms Xu.
Mr Liu and his team tended Yong Liang 24 hours a day, knowing that in the past all hand-reared pandas had died. 'It was complicated at first,' he says. 'We made a special formula, like the mother's milk. Without the correct one, the panda would die within a few days.'
Nowadays, Yong Liang eats the same as the other pandas: copious quantities of bamboo and muffins made of eggs, fruit, carrots and rice.