Wellington Zoo has put down its red panda Amy after she failed to recover from arthritis and kidney problems.
The zoo said the 15-year-old red panda was diagnosed in November last year and had been receiving treatment from its veterinary team.
However, during a health check today, staff found her condition had worsened and treatment was no longer effective.
The decision was made to euthanise her.
"These decisions are always hard, and it comes down to the animal's welfare and ensuring that we do what is in their best interests," Wellington Zoo chief executive Karen Fifield said.
"Amy was old for a red panda, and her health was deteriorating quickly. After careful consideration of whether we could provide treatment to manage her pain and health issues, it was agreed that euthanising her was the most humane and respectful thing to do."
Red pandas in the wild have an average life span of 8 years, just over half the age Amy was when she died.
Amy was part of the international breeding programme for red pandas, and produced two offspring while at Wellington Zoo.
Sir Ed was born in 2007 and now lives at Bristol Zoo, while Manasa was born in 2009 and still calls Wellington Zoo home.
Amy was popular with visitors, many of whom met her up close during close encounters.
Red pandas are native to the eastern Himalayas and southern China.
They spend most of their time up in the trees, and have a thumb and furry feet to help them grip.
The major threat facing red pandas in the wild is habitat loss through deforestation.