Giant panda "Bai Yun" poses with a birthday cake during her 22nd birthday celebration at the San Diego Zoo in San Diego, the U.S., Sept. 7, 2013. "Bai Yun" was presented a five-foot-tall, 215-pound ice cake right before the park was opened to the public. The zoo said the cake, which took four weeks to be created, was made of ice, bamboo, fruits and icing of pureed yam. [Photo: Xinhua/Zhao Hanrong]

Giant panda "Bai Yun" (Back), mother of six panda cubs, shares a cake with her latest offspring, one-year-old "Xiaoliwu" during her 22nd birthday celebration at the San Diego Zoo in San Diego, the U.S., Sept. 7, 2013. "Bai Yun" was presented a five-foot-tall, 215-pound ice cake right before the park was opened to the public. The zoo said the cake, which took four weeks to be created, was made of ice, bamboo, fruits and icing of pureed yam. [Photo: Xinhua/Zhao Hanrong] 

Giant panda "Bai Yun" (Back), mother of six panda cubs, shares a cake with her latest offspring, one-year-old "Xiaoliwu" during her 22nd birthday celebration at the San Diego Zoo in San Diego, the U.S., Sept. 7, 2013. "Bai Yun" was presented a five-foot-tall, 215-pound ice cake right before the park was opened to the public. The zoo said the cake, which took four weeks to be created, was made of ice, bamboo, fruits and icing of pureed yam. [Photo: Xinhua/Zhao Hanrong] 

Giant panda "Bai Yun" eats a birthday cake during her 22nd birthday celebration at the San Diego Zoo in San Diego, the U.S., Sept. 7, 2013. "Bai Yun" was presented a five-foot-tall, 215-pound ice cake right before the park was opened to the public. The zoo said the cake, which took four weeks to be created, was made of ice, bamboo, fruits and icing of pureed yam. [Photo: Xinhua/Zhao Hanrong]