A 27-year-old male panda at the Chongqing Zoo impregnated a female panda that gave birth to one baby panda in 1996. Last year, a 20-year-old female gave birth to two cubs.

After nearly eight years of research, experts in the zoo found that due to their decreasing digesting ability, giant pandas older than 19 years suffer from declining health that leads to their deteriorating reproductive ability, said the zoo's leading researcher Guo Wei.

The research group reached the conclusion based on the discovery of a large amount of mucus in the feces of old pandas.

According to statistics gathered from observing wild pandas, the group found that it takes a very short time for the food eaten by pandas to go through their alimentary canals. Periodic artificial feeding cannot meet the animals' natural habit of taking food from time to time.

Meanwhile, though of high nutritional value, the food for pandas in zoos is not helpful for the health of pandas' intestines and stomachs.

Based on their findings, the experts in the zoo, which started keeping giant pandas in 1962, improved the means of feeding and made modifications to the ingredients of their food. In addition, they keep control over pandas' sleeping schedule and weight.

The practise of the zoo has been approved by China's authoritative Wolong Giant Panda Protection Center and the China Zoo Association.

(Xinhua News Agency February 23, 2003)