The Best of "Jungle" Jack Hanna | Letterman

Jack Hanna Bitten by a Beaver - David Letterman December 1988

Jack Hanna Collection on Letterman, Part 1 of 11: 1985-1986

Jack Hanna's long goodbye: How Alzheimer's is stripping away the man the world once knew

Chris Elliott as Jack Hanna Collection on Letterman, 1986 (st.)

Jack Hanna Collection on Letterman, Part 11 of 11: 2013-2015

Jack Hannah @ Letterman