In this story, Horton discovers there is a microscopic community of intelligent beings called the Who's living on a plant that only he can hear. Recognising the dangers they face, he resolves to keep them safe. However, the other animals around him think Horton has gone crazy thinking that there are such beings.
Hans Conried
as Narrator / Horton / Dr. H. Hoovey (voice)
June Foray
as Jane Kangaroo / Mother Who / Baby Who / Cindy Lou Who (voice)
Chuck Jones
as Junior Kangaroo / Various Whos / Quizmo McKwoff / JoJo (voice)
Thurl Ravenscroft
as Wickersham Brother (voice) (uncredited)
