An “aggressive” dog is one which growls, bares its teeth, or bites inappropriately. Aggression can be an appropriate response to a particular set of circumstances. For instance, if you were being threatened by a stranger, you might be quite grateful for a dog that would growl and bare its teeth at that stranger. Similarly, a police canine responding under order from his handler, would not be considered to have an “aggression problem.” Aggression becomes a problem when it is considered by the owner or public to be “inappropriate” – displayed in the wrong context.
Dog trainers and veterinary behavioralists typically categorize aggressive behavior based on context. Doing so enables one to predict when aggressive behavior is likely to occur and may suggest possible solutions. We investigated the following aggressive diagnoses:
- Dominance Aggression
- Fear Aggression
- Interdog Aggression
- Protective Aggression
- Predatory Aggression
- Territorial Aggression
- Food-related Aggression
- Possessive Aggression
- Redirected Aggression
- Play Aggression
- Idiopathic Aggression
- Maternal Aggression
- Pain Aggression
The list above is in the rank order that such diagnoses are made at that behavior clinic. Other trainers and behavioralists may use slightly different lists. It is important to note that many, if not most, aggressive dogs have two or more forms of aggression. Below is a brief overview of each type of aggression listed above.
Dominance is a word frequently used in describing dogs. For the purposes of this article, a “dominant” dog is one which is quite assertive – in itself, dominance is neither good nor bad. A dog can be quite dominant, but not at all aggressive. That having been said, dominance aggression is the most common form of aggression seen in dogs and also the most complex. Dominant dogs will frequently push or lean on people, place their paws or head on people, straddle people, block access to doorways, prevent corrections by holding their leash or a person’s wrist, stare, “talk back”, be obsessive about “kissing”, etc. In the absence of snarling, growling, or biting, these are simply “dominant” behaviors. However, when snarling, growling, or biting are also present, the dog is generally diagnosed as “dominance aggressive.” These dogs may respond aggressively if stared at, toweled off, stepped over, pushed on, disturbed when sleeping or on furniture, verbally or physically reprimanded, etc. Dogs diagnosed as dominance aggressive have “control issues.” They are likely to exhibit other forms of aggression related to the control of “resources” such as property (territorial aggression), people (protective aggression), and objects (food related aggression and/or possessive aggression).
About 90% of dogs with dominance aggression problems are males and more of these are intact than neutered.* Unfortunately, neutering neither prevents nor cures dominance aggression, but is recommended as part of a treatment program since intact dogs are believed to respond more quickly when provoked, react more intensely, and behave aggressively for longer periods of time than their neutered counterparts. The onset of dominance aggression frequently correlates with maturity – generally between 18 and 24 months of age.
Current research is underway to determine whether dominance aggression is “organic” in nature. Work done at the University of Pennsylvania Behavior Clinic found that most dominance aggression dogs have abnormal metabolic screens in the absence of disease. The significance of these findings in the treatment of dominance aggression remains to be seen.
Treatment of dogs diagnosed with dominance aggression involves teaching the dog to defer to its people and most often requires that owners radically change the way they relate to their dog. Physical punishment is to be avoided since it not only puts the owner at risk but frequently escalates the aggression. This form of aggression is believed to be the number 1 reason dogs are euthanized for behavioral problems.
Fear aggression is aggression that occurs when the dog is frightened, regardless of whether or not there is something to be afraid of. The dog is frequently attempting to avoid an encounter by backing up while growling and becomes dangerous and bites or snaps when it is cornered. Sometimes these dogs will bite from behind and run away. In any case, it is inappropriate to physically punish these dogs as it simply reinforces their belief that there was something to be afraid of in the first place. Equally inappropriate is trying to soothe the dog while he behaves that way since that actually has the effect of rewarding the inappropriate behavior.
Treatment protocols vary somewhat and a procedure called “flooding” is sometimes used. Flooding involves putting the dog into the fear-evoking situation until the dog realizes that there is nothing to be afraid of. This is sometimes nearly impossible to achieve but may work in specific circumstances – ie: the dog is afraid of a hairdryer. More frequently a protocol of “counterconditioning” and “desensitization” is used. This involves teaching the dog a different response (such as sitting calmly) which will be rewarded while the inappropriate fearful response (for example, trembling, running away, barking, or growling) is avoided. Anti-anxiety medications are sometimes prescribed by veterinarians for use in conjunction with behavior modification.
Interdog (Dog-on-Dog) Aggression
Aggression towards other dogs is not always inter-dog aggression; it may be fear aggression or territorial aggression. Most instances of inter-dog aggression are between dogs of the same sex: two females fighting, or two males fighting, but this is not always the case. Often the dogs are of the same relative size and age, but often with dogs fighting who are residents of the same household, one is an older dog and the other is a younger one who lived in relative harmony until the younger one neared maturity. Hence, having dogs “grow up together” does not ensure that they will get along as adults. Most dog to dog aggression first presents itself when the dog is mature (roughly 18-24 months old). It is possible for a dog to live in harmony with another dog, yet not accept dogs who do not live in the household and vice versa. Also, dogs fighting with each other does not imply that either dog is going to be dangerous to people.
Treatment most often involves spaying and neutering the fighters followed by behavior modification. The exact nature of the treatment is determined by whether the fighters are members of the same household and basic obedience skills are essential. For dogs living in the same household where the aggressor does not abort aggression when the second dog capitulates (expresses submission), owners are sometimes better served to place the “victim” dog and to keep the aggressor as an “only pet.”
This form of aggression is characterized by a dog who perceives a threat to his owner, handler, or family member (maybe another dog) when there is no actual threat. Common scenarios involve the strangers or people known to the dog at the door, when someone approaches a car the dog is sitting in with his owner, or when another dog approaches. These dogs sometimes react to raised voices, and people hugging. The thing to remember here is that the protective aggressive dog is behaving aggressively when no real threat exists, which differs significantly from the same behavior when an actual threat does exist.
Treatment of these dogs involves avoidance of situations in which they are likely to behave badly until such time as they have mastered voice commands and readily take them from their owner. Once these skills are mastered, the owner can begin to desensitize and counter-condition the dog to behave differently.
Two types of behaviors commonly fall within diagnoses of predatory aggression. The first type is the dog that stalks “small prey” which can be birds, squirrels, cats, small dogs or other critters. These dogs may or may not be dangerous to infants, but because infants act in a manner similar to small prey, these dogs warrant special attention. The second type is the dog that chases moving objects such as joggers, bikers, skateboarders, etc. Some of what looks like predatory aggression may be territorial aggression. Dogs which are exhibiting territorial aggression generally have a “boundary” where the behavior starts and stops – for example, it occurs when the dog is home, but not when taken to the park for an outing.
Some sources indicate that this type of aggression cannot be successfully treated while others report success using a “negative reinforcer” which has been taught to the dog. Some predatory dogs do well with children, but it is important to exercise caution regardless of your belief or the pet’s training. In other words, never trust any dog alone with an infant – or child, for that matter. Further, dogs which kill other animals (regardless of species) should never be off leash, unsupervised, or confined in invisible fencing that another animal might cross.
The dog which is territorially aggressive defends space – for example, his yard, his crate, or his “personal space” – a mobile area encompassing a certain distance around himself. The hallmark of these dogs is that they are not aggressive when they are moved out of their territories – except for the dog with the “personal space” issue whose area moves with him. The use of fences frequently sets up clear boundaries for the dog to defend and restricting the dog with a chain seems to have the same effect.
Dogs with territorial aggression should not be left unattended in their yards since they pose a risk to any animal or human not cognizant of where the boundary is. This is particularly true of electronic (invisible) fences. Agitated and/or motivated dogs will cross the electronic barrier regardless of the shock. Further, unattended dogs get to “practice” aggressive behavior (chase away intruders) which is a self-rewarding behavior that results in heightened future aggression.
As the name implies, this is aggression that occurs in the presence of food or “food-type” items such as rawhides, bones, treats, etc. This form of aggression directed towards people is believed to be the best early indicator that dominance aggression is likely to develop. There are dogs that are food-aggressive only to other animals in the household. Severity varies from growling to snarling, lunging and biting; generally the higher quality the food the more severe the aggressive response to a real or perceived threat.
In most cases, avoidance is easier than treatment – simply feed the dog where he can be left undisturbed and do not give the dog access to food type resources that elicit bad behavior – for example, your dog does not need rawhides to survive – just don’t give them to the dog. In some cases, the dog protects only what it perceives to be a limited resource and once the object is no longer considered “special” it is no longer guarded – there are risks associated with this approach and so it most often does not appear in treatment literature.
Dogs with possessive aggression guard things (as opposed to food, space, or people). These dogs will not relinquish toys or stolen objects even if they present them to the owner in an apparent solicitation of play – when the owner reaches for the item, the dog growls, snarls, snaps, or bites. Statistics indicate that 25% of the dogs with this type of aggression exhibited symptoms before the age of 3 months and 50% showed signs before they were a year old.*
Treatment is accomplished through counter-conditioning.
The hallmark of this form of aggression is that it occurs when the dog is in the midst of another aggressive behavior – for instance, the dog is fighting with another dog and the owner reaches for the dog’s collar and is bitten. Most often it is in response to an attempt to interrupt the aggressive episode the dog was already involved in.
Treatment is the treatment of the other forms of aggression presenting – when the dog no longer fights with other dogs (for example), it won’t be necessary to interrupt a dogfight and no redirected aggression will occur. In the meantime, avoidance is the best policy – keep a leash on the offending dog at all times when it is supervised and confined when it cannot be supervised.
Barking, growling and snapping while playing with people and other dogs indicates play aggression and it usually occurs in younger dogs. These puppies grab fingers, hands, legs, and clothing or will grab your hand or arm instead of a toy you are holding. There is such thing as play growling which is not indicative of aggression – play growls are usually high-pitched, short, and frequently repeated as opposed to the lower pitched sustained growls of a serious threat. However, some dogs do not change their pitch when growling or change it so quickly that the owner has no time to react. These dogs often raise their hackles, flatten their ears, and dilate the pupils. Play aggression may become self-sustaining since play is a rewarding activity and some sources have reported that the dog may become more aggressive to evoke a response from the owner.*
Treatment: most dogs can learn that if they behave too roughly, the game is over – the owner simply stops playing. For those dogs that won’t take “no” for an answer, non-physical corrections are indicated. Canned air (like that sold for dusting computers) and water are first choices (water can be sprayed from a water pistol, squeeze bottle, or plant mister set on the “stream” setting). Do not rough-house or play tug or other rough games with your dog. If the dog behaves in this activity when you attempt to take away a ball the dog was fetching but now won’t relinquish, try playing with several objects – when the dog returns with the retrieved item but won’t give it up, throw a different item.
Idiopathic aggression is an unprovoked, unpredictable form of aggression with no known cause. Dogs frequently get a “crazed” look seconds before they become violent. This form of aggression is very difficult to diagnose correctly because the age of onset is 1-3 years which corresponds with the age that dominance aggression and idiopathic epilepsies first present and the symptoms of this disorder are very similar not only to dominance aggression and epilepsy but numerous other medical behavioral disorders such as rage syndrome.
Dogs suspected of having this form of aggression should always be treated by a veterinary behavioralist to get a correct diagnosis. Many of these dogs have medical problems which can be identified and treated (for example, epilepsy). For those dogs which are truly idiopathic aggressors, the prognoses are poor. The unpredictability and violence of their outbursts make it dangerous to live with them. It is probable that there is a genetic or medical basis for the behavior of these dogs, but until it is identified and understood, treatments will likely remain largely ineffective. Some dogs do respond to various drugs – and these can only be appropriately prescribed by a veterinary behavioralist.
Maternal aggression occurs only during pregnancy, “false pregnancy”, and in the presence of pups. Mother dogs sometimes “guard” their babies from very long distances and generally do not bite unless the puppy or toy (which the dog perceives to be a puppy during a false pregnancy) is taken. Repeated perceived threats may cause the mother dog to kill and/or eat the puppies.
Treatment is 100% effective by spaying the affected dog once the false pregnancy has passed or the real puppies have found new homes.
As the name implies, this form of aggression is a response to pain the aggressive dog is experiencing. This pain can be acute as in a sudden injury (hit by a car) or chronic (as in hip dysplasia). Most dogs suffering pain aggression will warn first, but not always.
Treatment involves pain management. Veterinarians have to contend with this type of aggression frequently and may do so using muzzles (to limit damage) or by using sedatives or anesthesia to treat the dog. Children are also victims of this type of aggression since they frequently make poor decisions (play roughly) and are uncoordinated when playing sometimes tripping over or falling on a dog. Children as young as 18 months can be taught to treat a dog gently and approach it safely. Children and dogs should always be physically separated when there is no adult present to supervise both in a direct line of sight.