DENVER - The Denver Zoo announced Friday that "Tawny," a 15-year-old female South African lion, has died following emergency surgery.

Zoo vets say they found multiple health issues from which Tawny would not be able to recover from during the surgery.
"Tawny was not going to be able to recover from these serious issues, and the most humane option was euthanasia. This is never an easy decision, but it was the right one," staff veterinarian Betsy Stringer said.

Veterinary staff euthanized her during the procedure Wednesday at the zoo.

"This is always so difficult. We've had Tawny in our family since the opening of Predator Ridge in 2004. She was an excellent mom and guests voted her 'Mother of the Year' in 2005," Denver Zoo curator of large mammals Hollie Colahan said in a statement. "She was a wonderful animal, and we will miss her very much."

Zoo keepers originally noticed Tawny having some lameness in her front right leg. Staff continued to monitor her closely, and for a week saw that she was refusing food. Blood work found that she was anemic and exploratory surgery discovered undigested food in her stomach and multiple fluid-filled cysts on her liver which were pressing on her digestive system, making it extremely difficult for her to digest food, the staff said.

The median life span of lions in zoos is 16.8 years. Lions in the wild live approximately 15 years.

Tawny, born in September 1997, came to Denver Zoo from Ohio's Columbus Zoo in May 2004. In September 2004, she gave birth to cubs, females Saba and Sukari, and male Kamau.

Zookeepers say, at the time, the first-time mother was very attentive and willing to sacrifice her favorite treat "bones" so her cubs could have them.

The zoo is also home to five other adult lions all age 15.