Out For Blood

Dealing with canine “roommates” who fight and wound each other.


In the October 1999 issue, Dr. Ian Dunbar discussed some training options to deal with female dogs that squabbled constantly. One of his first questions to an owner in this situation, he said, is “Have you ever had to take one to the vet for stitches after a fight?” The answer in the situation he addressed in that issue was “No.” However, we’ve had a number of questions from people whose answer to that question was, “YES!” In this issue, Dr. Dunbar offers his suggestions for dealing with dogs (in a multi-dog household) who fight to the point of injury and bloodshed.


Out For Blood

In the last issue, I limited my advice to cases where dogs that live together are fighting, but they don’t do any real damage to each other. This month, I’ll deal with an entirely different question.

If your dogs are fighting, and are causing severe damage to each other – or one dog is causing severe damage to another – I’m sorry to say that you are dealing with the most difficult of all canine behavior problems, the one with the worst possible prognosis. Your options are extremely limited, because the treatment really should have happened when the dog was 4 1/2 months old, which is when dogs normally learn bite inhibition.

Short window of opportunity
Bite inhibition is without a doubt the single most important thing that dogs learn. It is even more important than learning to become socialized to people and other dogs, which is the second most important thing that young puppies should learn, generally before they are three months old and reinforced throughout their lives.

Bite inhibition is a learned response whereby the dog consciously and strongly inhibits the full force of his biting power. Most dogs display bite inhibition when they are playing together, but also when they fight; if a dog does not have bite inhibition, he could easily hurt or even kill another dog in a fight. You’ll notice that even when most dogs fight, it looks and sounds perfectly awful, but neither dog walks away bloody. This is due to bite inhibition.

Dogs who are given the opportunity to be properly socialized by other dogs and people learn bite inhibition in the process of playing and roughhousing as puppies. When a puppy bites another dog in play, the other dog tends to either YELP! loudly and/or leaps up and knocks the puppy over with a loud bark or growl; a bitten dog also tends to leave the game. This teaches the puppy that all the fun ends when he bites too hard.

By the way, this is the single most important reason that puppies should go to puppy class. If they are like most puppies, their veterinarians have suggested that they stay in social isolation from strange dogs for a month (giving their vaccinations time to establish protection from disease), and the puppy class is the best thing to get them play fighting and mouthing and biting each other again. Here they learn that gentle bites prolong the play session, and they’re a lot of fun, and that hard bites stop the play session because the “bitee” wants some time out to lick its wounds.

People can use the same tack to teach their puppies bite inhibition. If a pup bites you too hard, yelp loudly and walk away from the puppy; it’s a very effective method. What you don’t want to do is to try to get the puppy to stop biting altogether. The first goal should be to teach the dog to inhibit the force of its bite, then reduce the frequency. If you teach the puppy never to put its jaws on you at all, when it does happen (say, an accident where the dog’s paw gets stepped on), the dog will react with an over-strong bite because it never learned that a softer bite will suffice.

The reason why bite inhibition is more important than socialization is because no matter how hard you try to socialize a dog to people or other dogs, there are going to be times when it is not sufficient. For example, someone shuts the dog’s tail in the car door, or your socialized dog is attacked, very painfully, by another dog. In these incidents, your dog will normally respond by biting, whether it’s out of provocation or self-defense. Whether or not your dog does damage is pretty much pre-ordained by the level of bite inhibition that was established before it was 4 1/2 months old.

Without a doubt, the dog’s level of bite inhibition is the single most important prognostic factor which determines whether or not a fighting problem is easily resolved, or extremely difficult and potentially dangerous to even consider resolving. And a dog who has a record of attacking and actually hurting another dog clearly has a very low level of inhibition. It’s really a shame; his life is going to be much less pleasant than other dogs’ lives.

Put a muzzle on it
Bite inhibition can be taught to a dog later in life, but it’s one of the most time-consuming, difficult, and potentially dangerous things to teach an adult dog. It is much easier to teach bite inhibition toward people, because it is very easy for a trainer to pad himself up in a full body suit with a Kevlar sleeve and let the dog mouth and bite him, in order to teach it that gentle biting is appropriate, and harder bites are not appropriate. However, it is next to impossible, and certainly not fair, to do this with other dogs. Knowing that your dog mutilates other dogs, how can you set your dog up with another dog? You can’t.

Out For Blood

Basically, your options are limited to controlling the problem, using hefty amounts of common sense.

The first rule should be walk the dog on public property only when the dog is wearing a muzzle. It is just simply not fair to other dog owners to take an unmuzzled dog out knowing that it does not have sufficient bite inhibition to protect other dogs. I’ve heard people say, “Well, he doesn’t attack other dogs; I can control him.” The fault with that line of thinking is that another dog might attack him, and get grievously injured, and I would consider that YOUR fault, even though the other dog started it. Dogs with good bite inhibition can get in scuffles and no harm is done. Of course, you’d hope that the owners of other dogs could control their dogs, but you can’t count on it. Muzzle your dog when in public to protect all concerned.

Muzzle technology has improved quite a bit in recent years. I like the open-ended muzzles like the one on the dog in the photo above; several companies make very similar models. These are soft but strong fabric (usually nylon) muzzles that control the dog’s biting, but are open in the very front to allow the dog to drink, lick his lips, and accept a treat. Since the goal is to train the dog to enjoy the company of other dogs, and to behave appropriately (sit, settle down, and be calm), wearing a muzzle that allows him to take treats (while keeping him from biting, of course) is critically important.

Learning to get along
You can live with these dogs permanently separated, juggling them around from room to room, but it’s a fairly difficult thing to do in most houses! But with the muzzle, you can now consider bringing the dogs together at times. However, I would insist on muzzling both dogs; it’s only fair. If you allow the good dog to bite your muzzled dog, you will only reinforce in his mind that the other dog should be bitten.

Now, with the dogs muzzled, you can start some very simple exercises to begin to condition the biting dog to begin associating the presence of the other dog with good things, not bad things. Put the (muzzled) biter on a leash, and sit down on the sofa, petting the dog. Have someone else enter the room with the other (also muzzled) dog, and then leave after a few moments. Have the other dog and person repeatedly enter and leave the room.

You are going to give the biting dog two types of feedback. When the other dog leaves, you totally ignore it. When the other dog comes in, you praise your dog and offer it pieces of kibble and maybe treats, even if he’s growling and putting his hair up.

But wait, you say! Isn’t that going to train the dog to growl and put its hair up? According to the laws of operant conditioning (the dog growls and it gets a treat), the growling is likely to increase in frequency. However, the growling doesn’t exist on its own; the dog is growling for a reason. If you give the dog a piece of kibble when the other dog comes in, you are classically conditioning the dog to form a positive association with the other dog’s entry and presence. Whenever you are training a dog in these two ways, the operant conditioning is temporary; the classical conditioning will win out. Eventually, the dog will form a positive association about the other dog, at which point he will cease to growl, because he has no reason to. So, I wouldn’t be too concerned with the fact that the dog is growling or has his hackles raised. The main thing you want the one dog to think is, “I don’t particularly like that dog, but I love it when he comes into the room, because my owner talks to me, pets me, and gives me kibble.”

For the next step, do the same exercise, but with the positions reversed. The other dog is in the room, and you enter and exit with the biting dog, giving him treats when you enter the room, and ignoring him when you leave.

Do not punish!
I should mention that the worst possible thing you can do – even if the dog growls and threatens the other dog – is to yank on the dog’s leash or spank it or yell at it. If you constantly reprimand the dog whenever another dog is present, you will reinforce your dog’s negative feelings for other dogs! Think about it! I suspect that this is 90 percent of the reason why dogs fight. Initially a dog fights because he meets another dog that he doesn’t like. But then he quickly learns that when other dogs approach, his owner gets upset, sweats, her heart rate goes up, and she shouts and jerks the leash. So the dog learns to try to keep other dogs away. He sees another dog and he says, “Get away, get away, don’t come close! My owner is unreliable around other dogs!”

I would like to add that in my video about training dogs that fight, at one point, I actually do raise my voice and reprimand a dog. This is one of those unfortunate things that can happen when you are trying to make a television program and working with two very difficult dogs and the producer is saying, “Hurry up and get something done!”

I fully regret departing from my usual training methods in order to accommodate the television crew; I would never do it again, no matter what the production crew wants. If they don’t have the patience to wait around for the result, then they won’t get it on film.


-By Dr. Ian Dunbar

Dr. Dunbar’s newest instructional videos, “Dog Aggression: Biting,” and “Dog Aggression: Fighting,” discuss all aspects of dealing with aggressive dogs.