(PUEBLO, Colo.) — The Pueblo Zoo announced the death of two elderly muntjac deer, Tinkerbell and Wendy, on Tuesday, March 11.

According to the Pueblo Zoo, the Animal Care team recently made the difficult decision to humanely euthanize the two deer after monitoring their declining quality of life due to advanced arthritis and age-related complications.

Courtesy: Pueblo Zoo, Photo shows Muntjac Deer at Pueblo Zoo

Courtesy: Pueblo Zoo, Photo shows Muntjac Deer at Pueblo Zoo

“Our geriatric muntjac deer had far exceeded their typical wild lifespan thanks to consistent medical care and nutrition,” said Gina Gley, the zoo’s Director of Animal Care and Conservation. “When animals reach advanced age, we carefully balance extending their lives with their comfort and dignity.”

According to Gley, muntjac deer usually live 10-13 years in the wild, while Tinkerbell and Wendy, a mother and daughter pair, had reached 17 and 18 years.