American-born panda Tai Shan enjoys the snow scene in Wolong Nature Reserve in southwest China's Sichuan Province, Feb. 17, 2010. Tai Shan is adapting well to life in his new home in southwest China's Sichuan Province after returning to China. He will begin to receive visitors on March 5 after one-month quarantine. [Xinhua/Chen Xie]

Tai Shan was supposed to return to China at the age of two. The Chinese government agreed to postpone its return twice in 2007 and 2009 at the request of the National Zoo.

Tai Shan's father Tian Tian, 13, and mother Mei Xiang, 12, are due to return to China in December next year.

According to the agreements reached by Chinese and American authorities, giant pandas are only loaned to the United States for scientific studies -- such as Tai Shan's parents, and all their cubs must also be sent back to China.

Thirteen Chinese giant pandas are in four zoos in the United States.

Giant pandas, known for being sexually inactive, are among the world's most endangered animals.

About 1,600 giant pandas live in China's wild, mostly in Sichuan and the northwestern provinces of Shaanxi and Gansu. Another 290 are in captive-breeding programs worldwide, mainly in China.