A correspondent recently asked if geneticists feel that aggression against dogs is a separate issue genetically from aggression against humans. The best source of this type of information is Scott and Fullers book, Genetics and the Social Behavior of Dogs, Chapter 3. Definitely a gold mine of stuff.
Let me instead answer from a behavioral point of view. Behaviorally, interdog aggression is separate from aggression to humans. (Which would obviously make it genetically different). When looking at aggression exhibited by dogs, behaviorists note some risk factors -- and it is wise you look at medical reasons simply to rule out medical causes since there are over 50 medical reasons for aggression.
Unfortunately, some dogs fit the "profile" of aggression (against both dogs and people) for dominance aggression. There are over 20 identifiable actions the dog may make to signify escalating aggression -- and it is possible that dogs with drop ears - like the Rottweiler or mastiff; dogs with normally slower movements -- like a Saint or Great Pyrenees; or dogs with different tail carriage -- like huskies or mastiffs; have more "bites" because people expect a mastiff to display the body language of a shepherd when it's going to bite.
It is highly likely bites will occur to the owner within the home, and children are often involved. Urban areas are more inclined to have dogs bites than rural areas with summers having more bites than winters. The greater the number of children and dogs, the higher likelihood of bites occurring.
"Some variation (additive genetic variance) must be present for the trait to be developed.... Protectiveness is a constellation of behaviors; breeding for this constellation produces a continuum of protective behaviors, some of which will not be what the selector desired. In fact some of the behaviors will be inappropriate because they are not compete or forceful enough and some will be unacceptable because they are too forceful and out of context ...
"Accordingly if one has developed a breed for certain specific behaviors, one should expect that there will be variation around that behavior and that some of this variation will result in inappropriate, out-of-context behavior. This means that if one has selected a breed for protectiveness or guarding, some of the individuals in that breed may inappropriately protect or guard ..."
With all groups of breeds, there is a tendency by some individuals to excuse some behavior - we might accept "mouthiness" in sporting dogs because they're sporting dogs, "snapping" in sighthounds, "guarding" in working dogs, growling in toys (because they can't really hurt you), herding dogs nip, you get the idea.
"Caution is urged in regarding any generalizations about inappropriate breed-based [author: or genetic based] behaviors. It is best to view selection for specific behaviors as a risk assessment analysis. Breeds that have been selected for one or a few particular traits may be more at risk of developing undesirable variation for those behaviors. This does *not* mean that dogs selected for protective behaviors are more aggressive than dogs for which this selection of trait is absent. It *does* mean that that particular breed may be more at risk for developing disproportionate number of dogs who exhibit out-of-context, inappropriate protective aggression."
I think I've wandered. Along the continuum of escalating aggression are signs given by the dog -- and whatever the consideration for "out of the blue" attacks, they seldom if ever actually occur. Also is the intensity of the attack. So we have two factors to consider, one being the "how mad the dog is" and the other "how important it is to the dog." My analogy would be if I pulled into a parking lot one day and somebody steals a parking place from me. I'm furious and mutter curses and shake my fist at someone but in the overall scheme of things in my life, it's a minor event. This does not mean I'm going to the parking lot with a gun and shoot someone. Contrast this with going to the bank, where they continually short me $10 when they give me change. And they do it again this time. Now, money is pretty important; and it happens again and again. I'm not going to stand for it any more, so my flash of amount of anger is smaller -- my blood pressure doesn't go as high in this case, but I am less likely to interrupt or inhibit my reaction when I blow up.
So along the continuum of risk assessment, a dog that is easily distracted from barking at the mailman -- protective aggression -- is not considered as much a risk as a dog who is laying down and staring at the door (a lower sign of aggression than barking), but who will not stop staring. So the signs were there -- let's see if we can see some of the classic ones.
Intact males are more likely to exhibit dominance aggression than neutered males or females. It is more likely that this is controlled by androgen since females who show aggression before puberty and who are spayed become more aggressive. Dominance aggression and protective aggression are the number 1 and number 2 causes of treatment by behaviorists.
From the description behavior, it might be possible to rule out actual interdog aggression. This is generally social in context and will occur between dogs within the same house, not hormone driven, although it generally starts at social maturity (18 to 24 months). The dog is challenged by a stare or a bump or body block, and then each dog behaves in reaction to what the other dog did. Strange dogs meeting -- even with two dogs fighting -- generally are responding to protective aggression (and the classic leash aggression in some cases). A characteristic of interdog aggression is that aggressive intention is not displayed to other animals. The dog may live amicably with cats and horses.
Protective aggression is stimulated by sudden movements. Frequently the dog inhibits the behavior in the absence of its owners (no owner to protect) or in strange places (dog shows are fine).
Dominance aggression occurs overwhelmingly in males (90% of cases), first obvious at social maturity (18 to 24 months), worsens with punishment, and may run in family lines. This type of aggression is the type which is looked for at the 8 week puppy test. If identified at that age, early intervention is required to save the dog; but not all dogs with dominant aggression can be identified at 8 weeks.
Most of us have dogs who display signs of territorial aggression: our dogs bark at someone at the door, protect the car, bark as people pass on the sidewalk. All social animals exhibit some protective aggression -- your neighbors ever throw trash on your lawn? This behavior is increased by fences; the dog is able to continuously "patrol" and protect, and the behavior is made extremely bad if the dog is in an electric fence or chained. It can also be made worse if "door greeting" abnormalities are tolerated: the owner greets someone at the door with the dog by the collar.
For dominance aggression, in contrast to protective aggression, there is more growling, snarling, biting, and staring. Barking is considered a sign of protective aggression -- think about barking dogs as you pass a yard. Dominance aggression is considered a concept of control, unlike possession of an object (food aggression) or challenge (will the dog get off the sofa or growl?). Dominance aggression is more common with men owners who like the concept of "big, tough dogs" and so some breeds might be more likely to be diagnosed. But the worse dominant aggressive dogs I have ever seen have been toy poodles and shih tzus - their behavior is more likely to be seen as innocent and owner tolerant.
There are some 15 things people do to exacerbate dominance aggression -- as simple as staring at the dog or pushing on their rump, leaning over them, making a leash correction. There are some 20 or so signs that the dog intends to become dominant aggressive -- as innocent as standing on your feet, leaning against you, "talking back," standing in front of you in the doorway, jumping in your lap. You can see how these signs are tolerated in smaller dogs.
Dogs with dominance aggression are categorized in behavior as those who think they are Master of the Universe -- able to control people and get things their own way -- a bad, bad prognosis usually. And then there are those dogs where all the signs were there. First, although other aggressive behavior is not a predictor for dominance aggression, dominance aggression is about control and the dog generally has another form of aggression also. Second, the dog has escalated through several signs of dominance aggression, standing on people, sitting in laps, and it's okay. Well, then the dog thinks it's in charge -- like when the teen-ager starts to talk back to test boundaries. This class of dogs will alter its behavior to the individual. The dog may not behave aggressively with an experienced trainer (the trainer is in charge), or when it's eating it may not bark at people passing by. The dog can interrupt and inhibit the aggressive behavior, but choose its time when not to react. This actually is the easiest dog to work with since the dog is capable of taking cues from context and behaving appropriately.
A long way around the subject to try to see that it would be extremely difficult to determine the exact genetics for this behavior, since development of the behavior depends not only on the genes but also the owner of situation. If the dog was genetically predisposed but owned by a good trainer and discouraged at an early age from barking at the door, it may not exhibit the trait. On the other hand, a dog who may genetically be less predisposed but encouraged to exhibit the behavior becomes a problem.
A note from author Barbara Nibling: I am a telephone engineer by profession but an avid dog hobbyist. I have Pembroke Welsh Corgis and a Cardigan, and I acquired my first purebred dog in 1972 -- a fear biter. Having progressed through being bitten by pets at training class, attacked by a Saluki at his home and by a Golden with food aggression, I decided it would be wise of me either to understand aggression or collect thimbles. This article is a result of the observations, seminars, and reading I have done.
Copyright 1998 Barbara Nibling. No reproduction or reprints of any kind without express permission of the author.