SINGAPORE - Inuka, the first polar bear to be born in the tropics, celebrated its 27th birthday on Tuesday (Dec 26) with a cake that featured a local twist.

Previous birthday cakes for Inuka usually consisted of an ice base and various toppings, but this year, the Singapore Zoo created one made of agar agar, to make it easier on its teeth.

Inuka, after all, has surpassed the average polar bear life span of 25 years, and would be 70 in human years.

"This polar bear could be my grandfather," said junior zoo keeper Stefan Ng, 29.

The cake, which had salmon on top, was presented to Inuka at its feeding session at 11am in front of a large crowd.

A contest was held, with guests who answered questions about Inuka correctly getting the chance to view it from a platform above its pond enclosure.

"It gave me a whole new perspective on the bear," said Miss Chua Jia Yi, a 22-year-old student who was one of the winners.

"I've seen the bear many times and I'm a big fan, but this was a new bird's-eye view, and we learnt much more because we got to talk to the keepers," she added.

Miss Chua said she saw that Inuka leaned slightly to the side, and was told this was due to arthritis.

The bear is on an animal care programme to tend to its arthritis and dental issues.

"The arthritis is our biggest concern, so we monitor him very closely and are regulating his diet so that he doesn't become overweight," said Dr Cheng Wen-Haur, deputy chief executive and chief life sciences officer of Wildlife Reserves Singapore, which runs the zoo.

Inuka, which measures 2.5m from nose to tail, currently weighs 513kg.

Dr Cheng added: "He would not be alive in the wild with his condition."

Inuka's parents Nanook and Sheba arrived at the Singapore Zoo in 1978. Its father Nanook came from Winnipeg Zoo in Canada and mother Sheba came from Cologne Zoo in Germany.

There was also Anana, a female polar bear caught in the wild, which arrived from Canada in 1979. It died in 1999.

Nanook died at the age of 18 on Dec 29, 1995, three days after Inuka turned five.

The locally born bear was raised by its mother Sheba, which died in 2012 at the age of 35. It was the second-oldest polar bear in the world back then.

Singapore Press Holdings (SPH) has supported Inuka's upkeep since its birth. SPH Foundation, the charity arm of SPH, took over the adoption from 2007.

Dr Cheng said Inuka will be the last polar bear to be kept in the Singapore Zoo due to new policies.

"Inuka has fully adapted to the climate here, but we want to put animals in their most suitable environments. So, for future polar bears, this would mean a lot of energy used to create the right habitat, which would cost a lot in carbon footprint and is not in keeping with our conservation message."