Jack Hanna

Jack Bushnell Hanna (born January 2, 1947) is a retired American zookeeper and a former director emeritus of the Columbus Zoo and Aquarium. 
His nicknamed was "Jungle Jack". He was director of the Columbus Zoo from 1978 to 1992
He appeared on many late night shows with Johnny Carson, David Letterman, James Corden, "Good Morning America", and Maury Povich.
In April 2021, Hanna was diagnosed with Alzheimer's disease.