Mei Xiang, mother of 4-year-old panda Tai Shan, rolls herself down a snowy hill on Tai Shan’s last day at the National Zoo in Washington, on Wednesday, Feb. 3, 2010. Tai Shan, who was born at the zoo in 2005, will be sent to China on Thursday to become part of a breeding program. Under the Smithsonian’s panda loan agreement, any cub born at the zoo must be returned to China for breeding. (AP Photo/Jacquelyn Martin)
