The World Wildlife Fund estimates that there were 1,600 pandas in the wild as of 2004. This figure is based on the work of researchers who spent several years in the mountains of China.
Since panda sightings are rare, researchers rely on waste matter containing undigested bits of bamboo. Individual pandas are identified by bite mark patterns, similar to the use of dental records in the identification of humans. The number of pandas in the wild has steadily increased since the 1970s. The World Wildlife Fund has been working with the Chinese government to secure existing panda habitats while creating new reserves.