Singapore: Singapore on Wednesday mourned the death of the first polar bear born and bred in the tropical island city, put down by wildlife authorities after a five-year battle with health difficulties stemming from old age.

Inuka, a 27-year-old animal who grappled with challenges ranging from arthritis to dental problems and ear infections, carried until his last days a green tinge in his fur blamed on algae growth.

"As much as we would like to keep Inuka with us for as long as possible, our ultimate responsibility is his welfare," said Cheng Wen-Haur, an official of zoo operator Singapore Wildlife Reserves. "The greater kindness would be to relieve him from prolonged suffering," Cheng said.

Calls for Inuka to be allowed to live out his natural life grew after the zoo operator said this month that the bear, whose age corresponded to 70 years in human terms, was sick. "Please do let him pass on naturally," said Vanessa S. Wee, one of more than 100 social media users who commented on the zoo operator's Facebook page.

"He is the only tropical polar bear, a true-blue Singaporean, a one-of-a-kind icon," added another, Anita Ryanto.

Inuka, or "foreboding strength" in Inuit, was born on Boxing Day in 1990 to parents Nanook and Sheba, who had arrived from Canada and Germany, respectively, in 1978. His father, Nanook, died in 1995 at 18 while Sheba died at the ripe old age of 35 in 2012.