Role in the film
When the wolf attacks, Katie and Lisbeth's screams alert Travis, who runs outside with a gun and sees Old Yeller fighting it off. Travis is able to shoot it, but not before it bites Old Yeller, and Katie sadly informs him that it, which attacked without provocation, was mad. At his pleading, she agrees to keep Old Yeller penned in the corn crib for a few weeks to chart his progress, hoping he will remain unaffected. At first he seems healthy, but one night he growls viciously at Travis, who tries to hide the affliction from the family.
- The dog who played the wolf was actually not a wolf at all. It was a German Shepherd made to look like a wolf. Both animals were trained to play-fight and were muzzled for that sequence.