Timeline of giant pandas at Zoo Atlanta

1997: Giant pandas Lun Lun (Aug. 25), a female, and Yang Yang (Sept. 9), a male, are born at the Chengdu Research Base of Giant Panda Breeding in Chengdu, China.

1999: Lun Lun and Yang Yang arrive in Atlanta on a United Parcel Service flight from Beijing (on Nov. 5).

2006: Female Mei Lan, first offspring of Lun Lun and Yang Yang, is born at Zoo Atlanta (on Sept. 6). Hers was the fifth birth in a U.S. zoo in six years. She was the only panda cub born in the U.S. that year.

2008: Male Xi Lan, second offspring of Lun Lun and Yang Yang, is born at Zoo Atlanta (on Aug. 30). He was the only panda cub born in the U.S. that year.

2009: Zoo Atlanta renews panda loan deal with Chinese government. New deal calls for the zoo to pay China $570,000 yearly during the next five years, compared with the $1.1 million that it paid annually over the last decade.

2010: On Feb. 4, Mei Lan, 3, is flown via a FedEx Express 777 Freighter to Chengdu Research Base of Giant Panda Breeding, where she will be a candidate for breeding. About 1,600 giant pandas live in the wild and about 300 in captive breeding facilities worldwide.