Mark Walton is a story artist and writer who works for Disney. He has provided voices for some of the characters in recent movies, including Barry and Bob the Texas longhorns in Home on the Range, Goosey Loosey in Chicken Little, and Rhino in Bolt. He is credited as a writer on the movie Tarzan and the animated short The Little Matchgirl. He is also credited as a storyboard artist on Home on the Range, and as a story artist for Chicken Little and Meet the Robinsons.
Walton was originally asked to voice Rhino in Bolt as a stand-in until an actor could be found and cast in the role. However, the directors liked his performance and decided not to hire anybody else.