Dickerson Park Zoo in Springfield is mourning the loss of its Malayan Tiger Petra.

The 18 year old tiger had to be euthanized today because of age-related health issues.

Here’s more from the zoo:

Dickerson Park Zoo is sad to announce that Petra, an 18 ½ year old Malayan tiger, was humanely euthanized today due to declining health from age-related issues.

Over the past month, Petra’s keepers noticed her slowing down and sleeping more; and in the past week, there was a significant change in her quality of life.

During a physical exam on Tuesday, radiographs and blood work revealed renal disease as well as vertebral spinal issues not uncommon in an older cat.

Like her name suggests, Petra was a rock.

After losing her front leg in an accident with the male tiger, Bunga, in September 2016, Petra recovered quickly, regained her strength and remained a favorite animal among zoo guests.

She was absolutely a favorite of the zoo staff.

“After the amputation her quality of life was good,” said zookeeper Jackson Thompson. “She chuffed every morning when we arrived. Her training was spot on and even her appetite and digestion improved.”

Senior keeper Melissa Dickson has worked with Petra since she arrived from the San Diego Zoo in 2004.

“Petra has always been a fighter; she’s always been feisty. The changes in her in the last couple of weeks let us know she was no longer comfortable, and we needed to do the right thing for her.”

The average lifespan of a Malayan tiger is 16 years.

Petra was one of the oldest Malayan tigers in an Association of Zoos & Aquariums (AZA) accredited zoo.