OMAHA, Neb. (AP) — Zoo officials in Nebraska say a 15-year-old lion was euthanized because the animal’s health had deteriorated from a yearslong battle with cancer.

Mr. Big, a male African lion at Omaha’s Henry Doorly Zoo and Aquarium, died Thursday.

The zoo says Mr. Big was diagnosed with cancer five years ago and his condition had been closely monitored since then. In June, staff noticed he was lethargic and had lost weight. They later determined the cancer had spread to both his lungs and liver.

Mr. Big had fathered two litters of cubs since 2012.