More than 40 wild pandas, an endangered species considered a "national treasure" of China, are believed to be living near the northwestern Chinese city of Xi'an, local experts have said.

The number was confirmed through examining the hair, excrement, bite marks and footprints of pandas, said Wu Xiaoping, director of the Xi'an Wild Animal Management Station.

"Bite marks, like human beings' fingerprints, are exclusive to a certain giant panda," Wu said. "Researchers have also conducted DNA analysis using the excrement of pandas to confirm their number."

China has carried out three nationwide censuses on pandas since the 1970s. According to the third census, launched in the early 2000s, the number of wild pandas living near Xi'an, capital city of Shaanxi province, rose to 41 from 18 in the 1990s.

"With the improvement in the ecology of the Qinling Mountains their current number should have increased again, or over 41 but less than 50," said Jin Xuelin, director of the Shaanxi Provincial Rare Wild Animal Rescue and Breeding Research Center.

The Qinling Mountains in the south of Xi'an are a major habitat for wild pandas in China, and the third census showed that the number of the endangered species in Qinling had risen from 237 in the 1990s to 273 in the early 2000s.

The census also showed that among the 1,596 pandas believed to exist in the wild in China, 1,206 are living in Sichuan province, which neighbors Shaanxi.