Bai Yun, whose name means ???white cloud,??? gave birth to her fifth cub at the San Diego Zoo on Aug. 5, 2009. The male cub, Yun Zi or ???son of cloud,??? can be seen daily alongside his mother. The first surviving giant panda born in the United States was born to Bai Yun in 1999, followed by cubs in 2003, 2005, 2007, and most recently Yun Zi. There are believed to be approximately 1,600 giant pandas left in the world. This critically endangered species is on loan to the San Diego Zoo from the People???s Republic of China to study this endangered species. As part of this long-term program, the San Diego Zoo is collaborating with the Chinese Academy of Science in studies of behavior, ecology, genetics and conservation of wild pandas living in the Foping Nature Reserve. The Zoo is home to five giant pandas.