Wellington Zoo's team is mourning the loss of their oldest cheetah, Charlie, who died on Friday aged 13.
Charlie was euthanised following a deterioration in his health which could no longer be managed, said senior vet Baukje Lenting.
"We have been monitoring Charlie's health closely over the last few weeks, as he was going off his food periodically and showing signs of abdominal discomfort.
"Charlie had regular medical examinations as he was affected by chronic pancreatitis."
On Friday, the animal care and veterinary teams carried out an endoscopy and ultrasound to look at his digestive system and take samples of his pancreas.
During this procedure, the team found other health issues developing internally which would be very difficult to manage and would affect the cheetah's health and well-being, especially at his age.
Being a good zoo was about ensuring animals' welfare needs were met, including maintaining their health and well-being, so the decision for Charlie was made with care and professionalism, Lenting said.
Charlie was born at the Ann van Dyk Cheetah Centre and was hand reared at Cheetah Outreach in Cape Town, South Africa before arriving at Wellington Zoo with his brother Delta in 2005.
"He has been a real character and much loved by everyone at the Zoo who has cared for him," said Jo Richardson, animal care manager.
"Charlie has been a great ambassador for Wellington Zoo and his species, with thousands of zoo visitors meeting him as part of our Close Encounters programme which raises awareness about the vulnerability of cheetahs in the wild."
Wellington Zoo measures its animals' well-being by using the "Five Domains of Animal Welfare" which assesses the animal's physical well-being, emotional and mental state, as well as their behavioural and physiological needs.
Cheetah facts:
In the wild, cheetahs are classified as vulnerable by the International Union for Conservation of Nature (IUCN) due to human animal conflict.
Through the Wellington Zoo Conservation Fund, the zoo supports Cheetah Outreach's Livestock Guarding Dog Project - an initiative that works to resolve cheetah and human conflict in South African farmlands by training Anatolian shepherd dogs to chase wild cheetah away from the livestock they protect, ensuring the cats' survival.