Inuka, the first polar bear to have been born and raised in a tropical climate, was put down on Wednesday after a 5-year struggle with age-related health issues. 

Born at the Singapore Zoo in December 1990, Inuka spent all his days in a region where outdoor temperatures hover around 26 to 27°C (around 80°F) year-round. In the Arctic wilderness, polar bears face average temperatures ranging from -34 to 0°C (-29 to 32°F).

To compensate for the heat, the zoo kept their bears, including Inuka's parents and another now-deceased female, in a climate-controlled enclosure set at 12-13°C (54°F) and regularly filled it with piles of ice.

Despite these radically unnatural surroundings, Inuka appeared to thrive. He was a beloved attraction throughout his impressively long life – most captive polar bears do not make it past 25, and males in the wild have a life expectancy of 15-18 years.

According to the zoo, the decision to euthanize Inuka came after they observed a rapid decline in his already fragile condition. For the past several years, the bear had been on a special geriatric care regimen to address his arthritis, dental issues, and persistent ear infections, but beginning in January, his activity levels plummeted. Known for being highly playful, Inuka stopped engaging in swimming and enrichment activities and his slow gait stiffened to the point that he dragged his feet with each step, resulting in abrasions on his paw pads.

An exam performed earlier this month revealed a poor prognosis overall, and the zoo planned to wait several weeks to see if he got better.

Sadly, Inuka was faring no better as of this week, forcing staff to make the humane decision.

"Our decision to let Inuka go was made with the knowledge that his health issues have seriously impacted his welfare," Dr Cheng Wen-Haur, CEO and chief life sciences officer at the organization that runs the zoo, said at a press conference.

"It has been a privilege and honor being his caregiver. But, difficult as it may be, it would not have been fair to prolong his suffering," added Mohan Ponichamy, the deputy head keeper.

The zoo also remarked that they stand by their 2006 commitment to not bring any more polar bears to Singapore, based on a decision by its Animal Welfare and Ethics Committee. Inuka had been the park’s sole polar bear since his mother died in 2012.

Many animal advocates argue that polar bears should not be kept in captivity at all because it is impossible to recreate the physical and mental stimuli of their natural habitat. Bears in the wild are constantly on the move throughout their enormous territories, hunting and defending their resources from competitors.

“It's not possible to offer them any kind of diversion or activity in a zoo that can replace these lost challenges,” James Brückner, of the German Welfare Association, stated last year.