Kiki was the matriarch of the zoo's pride of African lions.
Veterinary staff had been monitoring and treating her for progressive spinal arthritis since she arrived at the zoo in 2015.
Because Kiki's pain levels were no longer manageable for her quality of life, zoo authorities decided to humanely euthanize her.
Kiki arrived at the Chaffee Zoo with her daughter Zamaya, and she gave birth to a male lion cub while in Fresno. That son, Kijani, is now a father at the Dallas Zoo.