Rhino is a hamster and one of the two tritagonists of Disney's 2008 animated feature film Bolt (the other being Penny).
He is Bolt's biggest fan. He has all but memorized every episode of the canine's TV show. So when Bolt shows up at his door, Rhino sallies forth in his hamster ball to help him out.
Though perhaps not the brightest of characters, Rhino does manage to help both Bolt and Mittens at times. Other than that, Rhino's function in the movie is more that of a "comic relief", offering little character development and personality, but quite a few humorous dialogues.
Rhino was also the central protagonist of his own short, Super Rhino, in which he got superpowers himself by Penny's father (just like Bolt). The short feature was added to the Blu-ray and DVD release.
Role in the film
Rhino is a hamster that Bolt and Mittens meet while they are trying to get food. He watches all of Bolt's episodes on TV, and claims himself to be Bolt's number one fan. Though he was at first living with an older woman in a trailer park among many other hamsters, he decides to join Bolt in his journey to find Penny.
Rhino's voice actor, Mark Walton, was originally a placeholder voice, but the producers loved Walton's take on the character so much that he became the official voice.
Rhino is the only character in the film who never realized Bolt's superpowers weren't real, with Bolt seemingly seeing it unnecessary to tell the truth. However, in the ending, he watches the Bolt TV show and deems it "unrealistic", implying that he learned of the truth after being adopted by Penny.
It was implied in the movie that Bolt's relation to Rhino changed as the dog realized that he didn't have any superpowers. At first, Bolt was amazed with Rhino's lively, energetic character. However, his simplistic, pedestrian view of himself and the world soon became a nuisance, and after Bolt's quarrel with Mittens, he decides to travel on without Rhino, leaving him behind in Las Vegas.
Rhino was listed #40 in Empire Magazine's The 50 Best Animated Movie Characters.