Not the Dog - Aggressiveness Towards Other Dogs Tips on Dog Behavior Excerpt reproduced on the web from the book Get Rid of the Problem, Not the Dog , by Rod Cassidy. Some dogs are more prone to fighting than others. They either act, or are, more aggressive for a variety of reasons. Amazingly enough, most dog fights do not result in serious injury. It is not a good idea to try breaking up a dog fight because you might end up being the one who gets injured.
Dogs act aggressively toward other dogs for a variety of reasons.
A puppy who was not properly socialized to other dogs, i.e., allowed to play or romp with various kinds, sizes, and both sexes of dogs, will naturally grow up feeling anxious and tense in the company of other dogs. Some dogs are not social because of their need to defend territory. The territory might be the yard, the house, or personal territory such as the food bowl or the bed. There are hormonal aspects to aggression toward other dogs. A female in heat, or with puppies, might act aggressively toward other dogs.