An An, the world’s oldest-ever male giant panda in captivity, has been euthanized at the age of 35, the Hong Kong zoo announced Thursday.

An An's health had deteriorated in recent weeks, with a severe decrease in physical activity and appetite, and he was euthanized by veterinarians early Thursday morning, a statement from the amusement park and zoo Ocean Park said.

The park said he was equivalent to 105 in human years, and that "the difficult decision" to put him down had been made for welfare reasons in consultation with Chinese experts.

Born in the wild of mainland China's Sichuan province, An An was one of a panda pair gifted to Hong Kong by Beijing to celebrate the second anniversary of the city's handover from Britain in 1999.

He and his mate Jia Jia spent the rest of their lives in Ocean Park.

They were a venerable pair – Jia Jia held the Guinness World Records for the oldest living panda and oldest panda ever in captivity when she died at the age of 38 in 2016.

A panda's average life span in the wild is 14-20 years, according to the World Wildlife Fund.

After Jia Jia's death, her surviving mate led a rather solitary life – in 2021, he celebrated his 35th birthday alone with a Haagen-Dazs fruit and bamboo ice cake, surrounded by a number of handmade birthday cards from the park's staff.

Political animals

Pandas are a top choice of diplomatic gift from Beijing, and An An and Jia Jia enjoyed a fair degree of political clout for zoo-dwellers.

When they first arrived in the city, then-chief executive Tung Chee-hwa said that their names would inspire Hong Kong to be stable (An) and achieve great performance (Jia).

And when news of An An's lack of appetite was announced last week, Hong Kong's chief executive John Lee called Ocean Park to express concern.

Ocean Park has set up condolence books in the exhibition hall that An An used to live in.

Within an hour of the park announcing his death, hundreds of tributes appeared on the social media post.

"Thanks for all the happiness you have brought us over so many years," user "Tang Cc" wrote.

"I really can't accept you passing away but I also can't see you suffering. I will be missing you," user "Tuan Yuan Panda" said.

Hong Kong has another pair of pandas – Ying Ying and Le Le – who were gifted by Beijing in 2007.

They hit the headlines recently for beginning to show mating behavior during the pandemic after almost a decade of disinterest.

Pandas are notoriously bad at reproducing, especially in captivity.

They are categorized as "vulnerable" by WWF with a record of 1,864 living in the wild.