Old Yeller is the titular tritagonist of the movie of the same name. He is a Mastador and a hero. At first, he causes trouble such as scaring Travis' mule, Jumper, and stealing food from his family, which angers him deeply. However, after Old Yeller saves Travis' younger brother, Arliss, from a mother bear, Travis changes his mind and grows fond of him. They become good friends and work together to keep the farm in order and safe. However, one night, when a wolf attacks, Old Yeller is bitten during the fight and gets rabies as a result. Travis is distraught about this, and reluctantly has to shoot him to put him out of his misery. Afterwards, he makes a grave for him and buries him in it, then he starts raising his son, Savage Sam, planning to make him just like his dad.
When he had rabies, Old Yeller's growls and snarls were really recycled sound effects from Tramp, from Lady and the Tramp, when he was fighting the rat.