Part of Dog to Dog aggression is Dominance Aggression. Establishing himself as leader. This occurs with both strange dogs, and dogs within a household.
For dogs within the household, it is best to let them work it out themselves, without interference. Often it resolves in a fairly quick amount of time, and any interference on your part will only prolong the issue.
When out and your dog exhibits aggression towards strange dogs, you need to look carefully and be sure of what you are seeing.
Dominance Aggression could be hazardous when two strongly dominant dogs meet. Watch for tails held high, and ears laid back. High-held heads are also signs of dominance, and steps should be taken to seperate the dogs.
Fear Aggression manifests itself when a dog feels cornered, and feels he must fight his way out of a situation. Ears laid flat against the head, head held llow and tail tucked between his legs while growling are sure signs of fear aggression. Remove your dog immediately as he may be a fear-biter, and take steps now to properly socialize him. Obedience classes are a must for a fear aggressive dog.
Introduction to Canine Mental Health
Do Dogs Get Depression?
When Anxiety Attacks[]
Biting the Hands That Feed You
Obsessive Compulsive Behaviors
Physical Issues

