In fighting between dogs can happen between dogs who have lived together for a very long time, or between dogs who have recently been introduced, i.e., you have taken on another dog as a companion to the one you already have; you are fostering a dog, etc. When it happens between two dogs who have lived together happily for a long time, it takes their human owners completely by surprise. The end result usually being that the human gets very upset, stressed, afraid, confused and anxious, which causes both dogs to do exactly the same thing.
While more in fighting occurs between dogs of the same sex, it absolutely can occur between a male and a female.
In fighting is almost always because the dogs are competing over who will be “the boss.” In order to avoid this problem, you mist make it clear that the CEO position in your pack is already filled and it is YOU! No negotiation.
You will sometimes hear that you should “let them work it out on their own.” WRONG! If you do that, you are not leading by example and you are not sending the clear message that you are in control and you make all the important decisions, including who stays, who goes, who eats first, who gets the toy, who gets attention, etc.
Never, ever, run screaming into a dog fight! You will escalate the situation and can very likely get bitten. NEVER try to grab your dog by the collar if he/she is in a fight.
I like air horns, pots and pans, a good heavy blanket and sometimes even opening an umbrella between two dogs can startle them enough to redirect them.
While obedience training alone will not fix this problem, it is a good foundation for your relationship with your dog and having the tools necessary to ask them for an alternative behavior besides fighting.
There is so much more that could be said on this subject and I urge you to educate yourself on the language of dogs, the psychology of dogs and the inter relationships of dogs and people if you are going to have a multi-dog household.
If you are experiencing this in your house, give us a call.