Is Lu Xin "married"? Is this cub her baby? They quickly sought answers.

Extracting and analyzing DNA from the mother and cub's feces, they ran DNA tests.

"After more than one year investigation, we found that Lu Xin had "married" a local wild panda named LZP 54, and gave birth to a baby in August 2012," Yang Xuyu, head of the province's Wild Animal Preservation Station, told Xinhua in an exclusive interview.

"Lu Xin's success means it's feasible to build up a population in small panda communities by sending 'strangers' to join the group," Huang Feng says.

During Lu Xin's disappearance, China made other efforts to boost the quantity and quality of panda population.

Despite Xiang Xiang's failure, three more captive-bred giant panda were successfully released in the Liziping reserve in 2012, 2013 and 2014. Authorities say another two pandas bred in captivity will be released into the wild soon.

Bamboo corridors

Meanwhile, researchers are trying to build bamboo corridors between the habitats of different panda groups, which have been isolated after the original homeland was cut into pieces by highways, tunnels or human residential areas.

The pandas have been placed under state protection since 1962. Thanks to ecological initiatives, strict laws and greater public awareness, the number of pandas in China's wild has increased to 1,864 by the end of 2013.

"The sacrifice each panda pioneer has made for the species' own survival will be recorded in the species' history," says Huang.

The average life of the wild giant panda is 15 years. Lu Xin, 11, has entered middle age. Like all mothers, she cares for her young in the hope that it will thrive. Huang's team of guardians is anxious to see her succeed.

Xinhua correspondent Yu Li from Chengdu contributed to this story.