Credits
Cast
Hans Conried
Narrator / Horton / Dr. H. Hoovey (voice)
June Foray
Jane Kangaroo / Mother Who / Baby Who / Cindy Lou Who (voice)
Chuck Jones
Junior Kangaroo / Various Whos / Quizmo McKwoff / JoJo (voice)
Thurl Ravenscroft
Wickersham Brother (voice) (uncredited)
Art
Philip DeGuard
Background Designer
Irv Wyner
Background Designer
Angel Esparza
Background Designer
Don Foster
Graphic Designer
Maurice Noble
Production Design
Directing
Ben Washam
Director, Animation
Chuck Jones
Director, Producer
Sound
Eugene Poddany
Music
Visual Effects
Phil Roman
Animation
Irven Spence
Animation
Hal Ambro
Animation
George Nicholas
Animation
Richard Thompson
Animation
Tom Ray
Animation
Carl Bell
Animation
Don Morgan
Layout Supervisor
Writing
Dr. Seuss
Teleplay, Producer, Book