Debby celebrates her 40th birthday in her enclosure in Winnipeg's Assiniboine Park Zoo in December 2006. (CBC)The Assiniboine Park Zoo's polar bear Debby, famous for being the oldest living polar bear in the world, is dying from age-related medical complications, zoo officials said Thursday.

Debby, now 41 years and eight months old, has suffered several strokes and is losing weight. Her "prognosis of recovery from age-related medical problems is not good," the zoo said in a release.

"It's very hard. It's difficult," said Harold Masters, Debby's zookeeper for almost a decade. "They're almost like — I don't want to say family, but almost like family."

Despite her ailing health, the bear continues to live in her regular zoo enclosure and is out to see "her public" most days.

"They are offering her special treats, special foods — like, she loves veggie dogs and smoked goldeye, a few things like that — so they're trying to give her things she really likes, just get a bit more weight on her," said zoo curator Bob Wrigley.

"Sometimes animals at the zoo look in pretty rough shape but then they rally and are around for a lot longer, so it's hard to tell with an older animal," he added. "We'll just have to wait and see."

Debby has been acknowledged as the world's oldest living polar bear by Guinness World Records and Polar Bears International Magazine, and appears to be one of the longest-lived bears of any species.

Orphan Russian cub

Debby enjoys eating and swimming, zookeepers said. (CBC)An orphan cub from the Russian Arctic, Debby came to the Assiniboine Park Zoo in 1967. She produced six surviving offspring with longtime mate Skipper, who died in 1999 at age 34.

Few polar bears reach 20 years of age in the wild, but many have survived into their early 30s in captivity.

At the time of her 41st birthday in December 2007, zookeepers described her as "playful in her senior years," and said she enjoyed swimming, submerging a plastic barrel in her pond and stalking ducks and other birds that landed in her enclosure.

"Her favourite pastime remains eating," they said, noting she weighed in at 300 kilograms.

Officials said Debby is "without a doubt" the most popular animal in the zoo's 104-year history, with more than 18 million visitors. She does not hibernate, and is on display year-round.

"A wonderful ambassador for her species, it is significant that she has survived to 2008, the International Year of the Polar Bear, so designated by Polar Bears International, which promotes the conservation of the species under threat by global warming," officials said.

Zoo officials said they wanted to inform the public about Debby's ailing health so people who enjoy seeing her could return for one more visit.

It could take years for the zoo to acquire a new polar bear, since the current bear enclosure is not up to provincial standards and the waiting lists for bear cubs for zoos are long.