Being an elderly cat, Rufus has very little interest in anything that other young cats do (like chasing mice). Despite this, he is shown to be very kind and warm as he was able to cheer Penny up in her time of sadness to never lose hope in getting adopted. In regards to mice, he has no interest in harming or chasing them, as shown by his willingness to help Bernard and Miss Bianca in their search for Penny.
Role in the film
Rufus first appears in the movie at Morning Side Orphanage where Bernard and Bianca are looking for clues to what might of happened to Penny. When Rufus sees Bernard and Bianca he tells them that they should probably leave because he'll be kicked out onto the streets if they are spotted and that he's too old to chase mice. Bianca tells Rufus that they won't be there long and Bernard asks Rufus what happened to Penny to which Rufus says that Penny ran away. Rufus also tells them that the last time he saw Penny she was sitting on her bed and was sad because on Adoption Day at the Orphanage a man and lady came and looked at Penny but chose a little red headed girl instead. Rufus tells Penny that she has to keep faith and shows her a blue bird outside saying that faith is a blue bird as you can't touch it or buy it or wrap it up tight, but it's there just the same, making things turn out right. Penny thanks Rufus for his advice and gives him two ginger snaps she saved from lunch and she tells him that they aren't supposed to do that but Rufus promises not to tell anyone. Penny then tells Rufus that she loves him and they hurry off to supper. Bernard then asks Rufus if there was anything else to which Rufus says that there was this weird lady who ran a pawn shop down the street with her partner who tried to give Penny a ride but he believes that Penny wouldn't have anything to do with them. Bernard and Bianca decide to go down to the pawn shop and investigate to which Rufus replies, "Two little mice? What can you do?"
Rufus doesn't appear again until the end where Penny is holding him while she is being interviewed by a news reporter on the day she gets adopted. It is presumed that Rufus was also adopted along with Penny.
John McIntire, who voiced Rufus the cat, was married to Jeanette Nolan, who voiced Ellie Mae. They also voiced characters together in The Fox and the Hound, where he was the Grumpy Badger and she was Widow Tweed.
In the scene where Penny is carrying Rufus off to supper, Penny grabs Rufus and uncomfortably carries him off in her arms, pushing him up with her knee as he begins to slip. According to Ollie Johnston, who animated the scene, this was done in order to show the tender affection between Penny and Rufus by having the cat to be too fond of Penny to complain, since it would have been easier for Penny to walk away and have Rufus follow her.
While Rufus had some doubts about the "weird lady" having any role in Penny's disappearance, the reason he never told anyone (besides Bernard and Bianca) about that is because no one bothered to ask him. This could imply that Penny was the only person in the orphanage who communicated with him.
During early development of Oliver and Company, in which Penny was to reappear (before being replaced by Jenny), Rufus was also set to reappear as well, showing that he had indeed been adopted by her, but they were both dropped from the film.