In a "difficult" decision, the staff at the Saskatoon Forestry Farm Park and Zoo have decided to euthanize what could be the oldest living capuchin monkey in the world.

"We've been managing her pain for quite some time, but we're at a stage where we just can't do that anymore," manager Tim Sinclair-Smith said.

Ma, a brown capuchin monkey, is 47-years-old; the average life expectancy for a capuchin monkey is 25 years. She has arthritis and is unable to put pressure on her back leg, and is on anti-inflammatory medications.

"She out-lived her sons, she out-lived her husband, she out-lived everybody," Sinclair-Smith said.

Ma came to the zoo from the University of Saskatchewan in 1974 and is its longest resident.

Sinclair-Smith said he was unable to find a capuchin monkey older than Ma in an international zookeeper database.

"We believe she’s the longest living capuchin in the world," Sinclair-Smith told CTV News.

"We’ve only been able to find one that was 45 years of age."

Ma’s life is coming to an end later this week.