<Ul> <Li> Jim Carrey as Horton, an outgoing, eccentric, big - hearted, loving, sweet, and thoughtful elephant and teacher in the Jungle of Nool . Horton has no tusks, lives by himself and possesses acute hearing abilities . </Li> <Li> Steve Carell as Mayor Ned McDodd, the mayor of Whoville . He has 96 daughters, 1 son named JoJo and a wife named Sally . </Li> <Li> Carol Burnett as Sour Kangaroo, who mistrusts Horton's inquisitive nature as a threat to her legal authority over Nool . </Li> <Li> Will Arnett as Vlad Vladikoff, a scary, savage, eccentric Russian - accented vulture hired by the Sour Kangaroo to steal Horton's clover . </Li> <Li> Seth Rogen as Morton, a mouse and Horton's friend in the Jungle of Nool . </Li> <Li> Dan Fogler as The Chairman, dedicated to Whoville tradition and mistrustful of Mayor McDodd . <Ul> <Li> Fogler also voices Yummo Wickersham, leader of the Wickersham ape tribe brothers . </Li> </Ul> </Li> <Li> Isla Fisher as Dr. Mary Lou LaRue, a professor at Who U . </Li> <Li> Jonah Hill as Tommy, a bear and one of Horton's students . </Li> <Li> Amy Poehler as Sally O'Malley, Mayor McDodd's wife and mother to Jojo and her 96 daughters . </Li> <Li> Jaime Pressly as Mrs. Quilligan, a bird and Jessica's mother . </Li> <Li> Charles Osgood as The Narrator </Li> <Li> Jesse McCartney as JoJo McDodd, Mayor McDodd's quiet son . </Li> <Li> Josh Flitter as Rudy Kangaroo, Sour Kangaroo's son . </Li> <Li> Niecy Nash as Miss Yelp, the Mayor's assistant . </Li> <Li> Laura Ortiz as Jessica Quilligan, a bird, Mrs. Quilligan's daughter and one of Horton's students . </Li> <Li> Joey King as Katie, a cute, but eccentric little baby yak . </Li> <Li> Bill Farmer as Willie, a bear and Tommy's dad . </Li> <Li> Heather Goldenhersh as Who Girl </Li> </Ul> <Li> Jim Carrey as Horton, an outgoing, eccentric, big - hearted, loving, sweet, and thoughtful elephant and teacher in the Jungle of Nool . Horton has no tusks, lives by himself and possesses acute hearing abilities . </Li> <Li> Steve Carell as Mayor Ned McDodd, the mayor of Whoville . He has 96 daughters, 1 son named JoJo and a wife named Sally . </Li> <Li> Carol Burnett as Sour Kangaroo, who mistrusts Horton's inquisitive nature as a threat to her legal authority over Nool . </Li>

Who is the mayor in horton hears a who