In Disney's Old Yeller, many scenes feature Yeller fighting other animals (hogs, wolves, cows).
How were these shot? Were real animals fighting each other?
Yes, those were real animals fighting, but they were not really fighting.
Spike, who played the role of Yeller, was trained under an animal trainer, Frank Weathermax. The fighting scenes that you see in the movie were controlled and well rehearsed before the actual shooting and they are actual animal actions.
The most intriguing fight scenes are the fights between Yeller and a wolf and Yeller and a bear.
In case of the Wolf-Yeller fight, the Wolf was a German Shepherd who was made to look like a wolf.
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.
The bear used in the Bear-Yeller fighting is a nine-year-old movie bear, Doug owned by professional handler Byron Nelson.
For sheer excitement, few animal scenes in Hollywood history rival the furious bear and dog fight. Unusual preparation was necessary to stage the outdoor battle without harming either animal.
With their welfare of first consideration, rehearsals for the skirmish began months ahead of actual shooting. Spike, the trained dog who plays Old Yeller, spent weeks on a leash getting acquainted with Doug, a nine-year-old movie bear owned by professional handler Byron Nelson.
Each animal learned the others advantages. Spike was long on agility, Doug on strength.
This gives you a good insight into the making of Old Yeller and other animal fights.
Actually you can check this wonderful video and see how they were controlled by the trainers and the sounds were added and other fun stories behind the movie.
See Old Yeller's tail wagging? Notice there is no hair standing up on the necks of either dog? These are trained play scenes with an overdub of growling to give the appearance of a fight. Granted, the ASPCA didn't oversee all movies back in those days, but you can bet Disney wouldn't allow animals to get harmed by forcing them to fight.