Boris, the Mill Mountain Zoo’s male snow leopard, has died.

Zoo officials told The Roanoke Times that they euthanized the 19-year-old leopard Friday after he had failed to respond to treatment.

He wasn’t eating well or moving and was receiving pain medication for comfort.

Boris arrived at the zoo in 1996, giving visitors a chance to see an endangered species. About 5,000 snow leopards remain in the wild.

The zoo has another snow leopard, China, who arrived there last year.