Oldest giraffe in captivity euthanized at Tennessee zoo

"Patches" was put to sleep Thursday at the age of 31. (Photo: Zoo Knoxville)

KNOXVILLE, Tenn. (WTHR) - The oldest giraffe in captivity in the United States was humanely euthanized Thursday morning due to failing health.

Zoo Knoxville said 31-year-old "Patches" had to be put to sleep when her caretakers determined that arthritis had brought her quality of life to a turning point. She was placed on medication about a year ago when she started showing signs of stiffness.

In recent weeks, Patches' physical health began to show noticeable decline. That's when her caretakers and veterinarians reached the difficult decision to humanely euthanize her.

The average lifespan for a reticulated giraffe is about 25 years.