(CNN) - A beloved giant panda on loan to Thailand has died suddenly in a northern Thai zoo, prompting an investigation by Chinese experts.
Chuang Chuang, a 19-year-old male giant panda, was given to the Southeast Asian country in 2003 "to represent the relationship between China and Thailand," along with a female panda, Lin Hui, according to Chiang Mai Zoo's website.
Chinese state news agency Xinhua said the China Conservation and Research Center for the Giant Panda would send experts to Thailand to work with their Thai counterparts to establish the cause of the panda's death.
Thais woke up to the news of Chuang Chuang's death on Tuesday, with many mourning his passing on social media.
Chiang Mai Zoo director Wutthichai Muangmun said that Chuang Chuang was eating bamboo before he died, according to AFP.
"He was walking around, but staggered and fell to the ground," he told reporters.
The relationship between Chuang Chuang and Lin Hui became a source of public fascination as attempts were made to get the pair to mate.
Chuang Chuang was put on a low-carb diet and shown videos of mating pandas, but eventually the zoo resorted to artificial insemination and Lin Hui gave birth in 2009, AFP news agency reported.
A panda's average life span is 14 to 20 years in the wild, but the animals can live as long as 30 years in captivity, according to the World Wildlife Foundation.
Giant pandas were once regarded as endangered, but were reclassified as a vulnerable species in 2016.
Births are still significant for conservation efforts, with the animals famously hard to breed and female pandas only able to get pregnant once a year during a 24- to 72-hour window.
CNN's Jack Guy and Claudia Otto contributed to this report.