Chengdu 's panda experts improved breeding pandas in captivity . months , China zoo keeper had more than 100 pandas , now center has only 20 animals . Challenge is reintroducing captive pandas back into the wild .
China 's panda experts improved breeding pandas in captivity . 12 years ago , Chengdu zoo keeper had only 20 pandas , now center has more than 100 animals . Challenge is reintroducing captive pandas back into the wild .