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Aggression in Dogs

Updated: Oct 5, 2019

Understanding Aggression

Aggression is normal, adaptive behavior in virtually all animal species and domestic dogs are no exception. Animals have a variety of aggressive behaviors in their repertoires, to defend themselves from perceived threat as well as to compete for resources such as food, mates and territory. Also, as predators, dogs may chase and bite in the context of hunting for food. Selective breeding – domestication - has toned down or stylized aggressive and predatory behavior in most domestic dog breeds. Behaviors like watchdog barking, herding, pointing, compulsive fighting and retrieving are all modified forms of either aggression or predation. Most aggressive encounters are ritualized. Growling, snarling, snapping and biting without maiming force are all examples of ritualized aggression. Ritualization allows contests to be decided without the use of (more “expensive”) fatal or maiming force to either participant. We humans would like no aggression, even of the most ritualized sort, directed at us. To achieve this “no arguing” standard requires pro-active prevention programs for all dogs.

Aggression to Strangers

When a dog is uncomfortable around strangers, or certain strangers, such as men or kids, it is usually because she has been selectively bred as a guard dog and/or not been fully socialized. A socialized dog is comfortable around unfamiliar people. To become socialized, a dog must have sufficient exposure and positive experiences, especially when young. Aggression comes into the picture when the dog encounters something she is not socialized to. She will be highly motivated to increase the distance between herself and who or whatever is making her uneasy. She can achieve this in two ways: she can flee or she can try to make the person flee by behaving aggressively. The underlying motivation is anxiety.

Fear of novelty is a normal, adaptive trait in animals. In the case of dogs certain individuals, breeds and lines of dog are genetically more difficult to socialize. It takes greater effort, including formal behavior modification, to make them more comfortable with strangers. Sometimes only minor gains can be made and their environment must be managed more carefully, both to avoid risk to strangers and stress to the dog. A stranger may be a kind, gentle dog-loving person, but this is not relevant to an unsocialized dog. The fact that they are unfamiliar will provoke fight or flight reactions.

Aggression to Family Members

When dogs threaten or bite family members, the usual suspects are resource guarding and poor tolerance of body handling. Ritualized defense of food, mates, sleeping locations and other resources is an adaptive trait. This behavior frequently pops up in our pet dogs, in the form of possessiveness of anything from food dish and bones to sofas, tissues and even garbage! Luckily, there are exercises owners can do to make their dogs much more relaxed around resources.

Body handling problems are also common in pet dogs. Many will be naturally reluctant to have their bodies touched or manipulated, in certain places or in certain ways. If they are not taught to accept and enjoy handling, they may threaten or bite in this context. Gradual exercises can desensitize dogs to being patted, hugged, grabbed by their collars and to tolerate having their feet, mouths, tails and bodies handled and restrained.

Bite Threshold and Combined Issues

A mild resource or handleability issue can combine with a mild or unnoticed socialization problem to produce a “sudden” biting incident. Although seemingly unprovoked, careful detective work often reveals that the dog had unaddressed problems in both areas. When these came together, the dog’s bite threshold was crossed. This is why veterinarians and groomers are bitten so often and so use preventative measures such as muzzles. Treating Aggression Dogs that are undersocialized can often be gradually improved with a combination of remedial socialization and classical conditioning. Both the speed and likelihood of improvement depend on the dog’s genetic make-up and the owner’s compliance with instructions.

Another important factor is how well developed the dog’s bite inhibition is. Young puppies learn “soft mouth” by play-biting other puppies constantly. When one bites another too hard, the hurt puppy will yelp and stop playing. Gradually, with repetition, the puppies learn not to bite too hard so that play can continue. This is called acquired bite inhibition. When humans forbid play-biting, puppies don’t get feedback on their jaw strength and are at higher risk to grow up without this important line of defense against aggression. Dogs with poor bite inhibition are more difficult to treat for any kind of aggression problem because of the dire consequences of any re-offenses along the way. When they bite, they inflict worse damage than soft-mouthed dogs. It is therefore extremely wise to allow soft play-biting from puppies and to target the harder bites with immediate non-violent consequences, such as time-outs, to teach the puppy to bite softly before teaching him to not bite altogether.

Most resource-guarders and hard-to-handle dogs can be improved with desensitization and counter conditioning exercises. Prognosis depends on owner compliance, the presence of protracted warning signals – stares, growls, snarls and snaps – and the degree of bite inhibition.

Dog-Dog Aggression

Some dramatic looking, non-injurious squabbling between dogs is normal – it is the dog equivalent of arguments. Problems arise when altercations are non-ritualized (i.e. dogs are being seriously injured) or when the incidence is greatly elevated. Luckily, there are a number of things dog owners can do to minimize the frequency and intensity of dog to dog aggression.

On-Leash Aggression

Dogs are highly social. When most dogs spot another dog on the street, they are highly motivated to approach and investigate. Being on leash restricts their ability to do so. The resulting frustration translates into increased excitement and agitation, which can be alarming to the owner, who may then restrict access, tense up before encounters or even punish the dog. This starts an association between the sight of dogs and frustration plus possibly punishment. A vicious cycle is then born that often culminates in thwarting-related or “barrier frustration” aggression. This is mainly why so many dogs are more aggressive on leash than off.

Part of the solution is recognizing the inherently abnormal situation of dogs meeting other dogs without freedom of movement. Owners can mitigate this by allowing dogs to approach and investigate friendly dogs or allowing them to do so after performing a “please may I” command such as “sit.” If a dog already has barrier-related aggression, changing the association from negative to positive, and remedial socialization can produce profound improvement.

Sibling Rivalry

Fights between dogs who live together are fairly common. Dogs compete for resources such as food, bones and owner attention. Many dogs are also sensitive about proximity and body contact. If the fights are not too frequent and are non-injurious, there are a number of options, including non-intervention. People sometimes argue and so do dogs. Fights are usually context-driven and, once the triggers are uncovered, management and time-out penalties for fights will bring relative peace. If the fights are damaging to either participant, efforts must be much stricter, with an airtight management regime usually being necessary.

Dog Park Fighting

Dogs can be bullies, competitive over resources, socially uncomfortable and defensive, and male dogs are at statistically higher risk to tangle with other males. If dogs play well usually but seem to target certain dogs for bullying, they can be given time-out consequences for their bullying behavior. Resource guarding dogs are rarely dangerous unless they inflict injurious bites to other dogs. If dogs are undersocialized, their confidence can be sometimes be gradually built up with exposure to the right dogs, or exercise options other than dog parks employed. And, it is difficult to overstress the importance of neutering male dogs, mainly to prevent their scent from triggering other males.

Preventing Aggression

Prevention of aggression is much easier than treatment. Socialize your puppy to as large a variety of people and friendly dogs as possible. Make it fun with lots of treats and playing. Practice anti-guarding exercises. Teach puppies to bite softly by using time-out consequences for hard bites before forbidding all play-biting. Handle your puppy all over and make it fun with treats and praise. Find and enroll in a reward-method puppy kindergarten class that covers these exercises and allows free puppy play. Maintain socialization and comfort around resources and handling in adult dogs with regular practice. Allow your dog regular opportunities to socialize with other dogs.

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