The Potawatomi Zoo announced on Facebook Tuesday that Tango, an African lion, died. The post indicates that Tango would have been 18 on Dec. 12.
The zoo says the median life expectancy for a male lion in human care is 16.9 years and in the wild it's 10-12 years.
The zoo says Tango had been treated for "age-related issues for the past few months." The post goes on to say Tango was "humanely euthanized" on Monday, Nov. 4 when his condition suddenly worsened.
The zoo calls Tango "one of the most iconic animals" at the location, "adored by staff and visitors alike."