"Lionel" had been in veterinary care for the past several months, according to the zoo, suffering neurological issues and incontinence. Staff decided the lion's quality of life was worsening and the decision to euthanize him was made. He was put down on Saturday.
Lionel came to live at the zoo in 1997. He was the only male lion at the zoo. He was 23 when he died, which is considered old for a lion. Lions in captivity live longer than those in the wild.
The zoo has one other lion, a 22-year-old female named "Cookie" that came to the zoo with Lionel in 1997.