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

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

A cheetah and mountain lion are among five animals that died after a bird flu outbreak at an Arizona ... a 20-mile drive northwest from downtown Phoenix.

PHOENIX (AZFamily) — The Phoenix Zoo had to make a tough announcement this week. Zoo staff made the difficult choice to euthanize one of the zoo’s two female mountain lions, Sierra, earlier in ...