Denver Zoo veterinarians have euthanized a female South African lion that had cancer and had stopped eating.
Zoo officials say Natal was euthanized Monday evening. She would have been 16 next month.
Lions in the wild live about 15 years. The median life span of lions in zoos is 16.8 years.
Natal's death came about a month after the zoo euthanized another 15-year-old lion named Rian that also had cancer. In February, the zoo lost a 15-year-old lion named Tawny that had cancerous cysts preventing the proper digestion of food.
The zoo is monitoring two other 15-year-old lions, one of which has cancer. The other has shown signs of appetite loss.
The zoo has one more 15-year-old lion, plus two 1-year-olds.