Giant panda Lin Hui, 21 years old, died at Chiang Mai Zoo in Thailand on early Wednesday, said the Consulate General of China in Chiang Mai on the same day.

Lin Hui had first exhibited unusual symptoms on Tuesday and was given treatment guided by experts from the China Conservation and Research Center for Giant Panda. However, the zoo failed to save Lin Hui.

The cause of Lin Hui’s death has not yet been announced.

Born in September 2001, Lin Hui was sent to Chiang Mai Zoo on Oct. 12, 2003 as a goodwill ambassador between China and Thailand.