PHOENIX — The Phoenix Zoo said goodbye to its 50-year-old Asian elephant, Sheena, for the final time Monday.

Sheena died in the morning after her keepers found her laying down in her barn and unable to get up.

She passed away a short time later of natural causes, the zoo said in a press release.

The Asian elephant had been in stable condition but was being carefully managed in recent years due to bouts with chronic osteoarthritis and gastrointestinal issues.

"Sheena was the 'sneaky one,'" Heather Wright, manager of elephants, said. "She wasn't outwardly rambunctious, but we'd hear her playing with toys in the barn, and when we'd come around the corner to watch her, she would freeze and give a look like 'What? It wasn't me!' and act innocent.

“It was so funny! Sheena was incredibly intelligent, extremely sweet and she seemed to love everybody."

Sheena had spent the past 21 years at the zoo after being brought over from the Ringling Brothers Center for Elephant Conservation.

She was a companion to 56-year-old Indu and Reba, who died in April 2020.

"She will be sorely missed by all her caretakers here at the Zoo, as well as our members and guests," Wright said.

The average life span for Asian wild elephants and elephants in managed care settings is 45 years old.

The zoo said it doesn’t have plans to acquire another elephant.