Zoo staff made the difficult choice to euthanize one of the zoo’s two female mountain lions, Sierra, earlier in the week.

The Phoenix Zoo lost its beloved mountain lion, Sierra, who was humanely euthanized this week after dealing with advanced renal failure. The Reid Park Zoo had to humanely euthanize their African lion, ...

The zoo said zookeepers and veterinary staff made the "difficult decision" to put down mountain lion Sierra earlier this week ...

Zoo staff made the difficult choice to euthanize one of the zoo’s two female mountain lions, Sierra, earlier in the week.

After 17 long years at the Phoenix Zoo, Sierra the mountain lion was humanely euthanized after experiencing renal failure, the zoo said on Feb. 27. She came to the zoo 17 years ago as an orphaned cub ...

The Phoenix Zoo lost one of its longtime residents this week. Sierra, a mountain lion, was humanely euthanized due to ...