PITTSBURGH, PA - Zoey, the sea lion who captivated Pittsburgh Zoo & PPG Aquarium visitors for 24 years, has died. The zoo announced Wednesday that the animal was euthanized after being diagnosed last year with oral squamous cell carcinoma.

Although Zoey was the first sea lion to receive an innovative cancer treatment called stereotactic radiation, her health declined after she initially responded well to the treatment.

"Zoey will be missed by not only her keepers and Zoo staff, but the many visitors who loved and supported her through the years as well," the zoo said in a statement.