ATLANTA -- Dennis Kelly, President and CEO of Zoo Atlanta, announced Tuesday that Masai, a 18-year-old female African lion, passed away.

Zoo Atlanta's animal management team had been treating the lioness's declining health since January 2008.

Remembered for her spirit and salty personality, the feisty big cat had been in good health until she began to suffer from what appeared to be an upper respiratory infection earlier this year.

While treatment had been successful to the extent that Masai's respiratory symptoms cleared, follow-up exams indicated that she had developed severe anemia.

"Our veterinary and animal management team worked diligently to ensure that Masai received the best care and treatment possible," said Kelly. "We will miss her here at Zoo Atlanta."

The elder lioness's passing occurred just weeks after the zoo's announcement that 5-year-old female Kiki had given birth to her first litter of cubs.

The three male cubs, healthy and thriving at 3 weeks old, continue to do well in their mother's care.

Zoo Atlanta's animal management team anticipates that the new arrivals will join Kiki on exhibit when they are between 7 and 12 weeks old.

Masai was one of three lions born on June 3, 1990, at the Chipangali Wildlife Trust, a wildlife orphanage in Bulawayo, Zimbabwe.

She and two males, Bantu and Zulu, were donated to the Riverbanks Zoo in Columbia, S.C., later that year.

Masai joined the Zoo Atlanta family on October 16, 2003.

While she did not reproduce at Zoo Atlanta, she gave birth twice at Riverbanks Zoo (a single cub born in April 1993 and a litter of two in August 1993).

The lioness's nearly five years in Atlanta were spent in an enriching environment in Zoo Atlanta's African Plains, and her long, full life is a testament to the expert professional care she received during her 18 years.

Zoo Atlanta houses three other adult African lions - males Farasi, 18, and Kamau, 3, and female Kiki, 5.