The lone polar bear, who had lived in the zoo since 2012, was put down after veterinarians noticed her condition decline and saw she was having problems holding down food.
Care teams began running tests in the days before when they noticed Rizzo had become lethargic and was having trouble eating. According to NBC News, they performed an abdominal ultrasound, conducted an endoscopic exam and drew blood, which led them to diagnose her with renal failure, a terminal condition that is common among polar bears.
“Due to her terminal diagnosis, the very difficult decision was made to humanely euthanize Rizzo, sparing her any discomfort” the zoo wrote in a Facebook post, which has since been flooded with condolences and photographs of the animal. “She passed peacefully, without any pain. Your words of support, photos and memories mean more to us than you know. Thank you so much for sharing your stories.”
Although polar bears can lived until into their 30s, their average life expectancy is between 15 and 18 years.