The Detroit Zoo says zookeepers have euthanized a female Canadian polar bear after it came down with cancer.
The zoo in suburban Royal Oak, Mich., says the 27-year-old bear known as Barle was put to death Wednesday after a physical exam discovered tumours in its abdomen.
The zoo says polar bears generally live 15-18 years in the wild and 25-35 years in zoos.
The zoo says zookeepers noticed changes in Barle's behaviour, including decreased appetite.
Barle was born in the wild in Manitoba and captured as a cub. It spent most of its life as a performing circus bear.
The zoo says Barle was rescued from the Suarez Brothers Circus in Puerto Rico and brought to the zoo in 2002.