Understanding Aggressive Behavior in Dogs

Aggressive behavior is part of the normal behavioral repertoire of almost any animal species, including dogs. Owners are sometimes confused as to whether or not their dogs are displaying aggressive behavior. What is aggression? Behaviorally, aggression is any behavior whose intent is to intimidate or harm another animal. Thus, growling, baring teeth, snarling, and snapping are all aggressive behaviors, just as is biting. Although aggressive behaviors are normal for any dog, they are generally unacceptable in most situations. From the dog's perspective, there is always a reason or motivation for aggressive behavior.
Because humans and dogs have different communication systems, misunderstandings may occur between the two species. A person may intend to be friendly toward a dog, or at least not threatening, but the dog may perceive the person's behavior as threatening or intimidating. Dogs are not schizophrenic, psychotic, crazy, or necessarily "vicious" when they display aggressive behavior. Dogs show aggression for many different reasons and often for more than one reason.

Dominance aggression is motivated by a challenge to a dog's social status or to its control of a social interaction. Dogs are social animals and normally live in groups or packs. Dogs view their human families as their social group. Based on the outcomes of social challenges among group members, a dominance hierarchy or "pecking order" is established. If a dog perceives its own ranking in the hierarchy to be higher than that of its owners, it is likely the dog will challenge the owner in certain situations. Because people do not always understand canine communication, they may challenge the dog's social position inadvertently, without even being aware they are doing so. Dominantly aggressive dogs may growl when disturbed when resting or sleeping, especially from a favorite spot such as the couch or the bed. Physical restraint, even when done in a friendly manner like hugging may also cause the dog to respond aggressively. Reaching for the dog's collar or reaching out over its head to pet it can be interpreted by the dog to be dominance challenges. Dominantly aggressive dogs are often described as "Jekyll and Hydes" because they can be very friendly when not challenged. Dominance aggression can be directed at people or at other animals. The most common reason dogs in the same family fight with each other is because of an instability in the dominance hierarchy. This often occurs when owners try to treat both dogs equally, rather than allowing one dog to establish dominance over the other.
Fear motivated aggression is a defensive reaction and occurs when the dog believes it is in danger of being harmed. Remember it is the dog's perception of the situation, not the intent of the human which determines whether the situation is potentially harmful. For example, you may be raising your arm to throw a ball, but a dog may perceive this to be a threatening arm movement and bite you because he believes he is protecting himself from being hit or struck. A dog may also be fearfully aggressive when approached by other dogs.
Protective, territorial, and possessive aggression are all very similar, and involve the defense of valuable resources.
Territorial aggression is usually associated with defense of property. However, a dog's sense of territory may extend well past the boundaries of his yard. For example, if a dog is walked regularly around the neighborhood, and is allowed to urine-mark, then to him, his territory may be the entire block!
Protective aggression usually refers to aggression directed toward people or animals whom the dog perceives as threats to his family, or pack. Dogs become possessively aggressive when defending their food, toys, or other valued objects such as Kleenex stolen from the trash!
Redirected aggression is relatively common but is behavior that pet owners may not always understand. If a dog is aroused into an aggressive response by a person or animal whom it is prevented from attacking, it may then redirect this aggression onto someone else. A common example occurs when two family dogs become excited, bark, and growl in response to another dog passing through the front yard. The two dogs, confined behind a fence, may turn and attack each other because they cannot attack the intruder.
Predation is usually considered to be a unique kind of aggressive behavior, because it is motivated by the intent to pursue, kill, and occasionally consume. The prey in this case may be small animals such as birds, rodents, small dogs, or even small cats or small children. Dogs should never be left alone with an infant, as the child's uncoordinated movements and high-pitched vocalizations can elicit predatory responses in some dogs.

Individual Variation

Dogs differ in their likelihood to show aggressive behavior in any particular situation. Some dogs tend to respond aggressively with very little stimulation. Others may be subjected to all kinds of threatening stimuli and events, and never attempt to bite. The difference in this threshold at which a dog displays aggressive behavior is influenced by both environmental and genetic factors. If this threshold is lowered, a dog will be more likely to bite. Raising the threshold makes a dog less likely to respond aggressively. This threshold can be raised or lowered using, behavior modification techniques. How easily this threshold can be changed is influenced by the dog's gender, age, breed, general temperament, and by whether the appropriate behavior modification techniques are chosen and correctly implemented. Working with aggressive animals can be a potentially dangerous undertaking, and should be done only by or under the guidance of an experienced animal behavior professional who understands animal learning theory and behavior.

Use of Punishment

Punishment alone will not make a dog less aggressive. If the aggression is motivated by fear, punishment will only make the dog more fearful, and therefore more aggressive. Attempting to punish or dominate a dominantly aggressive dog is likely to cause the dog to escalate his behavior in order to retain his dominant position. This is likely to result in a bite or severe attack. Even if one person can successfully intimidate the dog, it is highly unlikely that everyone else the dog encounters will be able to do the same. Punishing territorial, possessive, or protective aggression is likely to elicit additional defensive aggression.

Appropriate Behavior Modification Techniques

With the use of techniques called counter conditioning and desensitization it is possible to teach the dog a new, non-aggressive response, and significantly raise the threshold at which aggressive behavior is likely to occur. In order to be successful, these procedures must be implemented in a series of very small increments or steps. If done incorrectly, these techniques can make the problem worse, and may put people in danger. They should be implemented by, or under the direction of, an animal behavior professional who understands animal learning theory and behavior.

Preventing Problems

   Because both environmental and genetic factors influence how readily any dog will display aggression, dog owners can take several steps to prevent aggressive behavior problems from developing. Dogs with aggressive behavior problems should NEVER be bred, as they can pass these behavioral tendencies along to their offspring.
   Between the ages of 4 and 16 weeks, puppies experience a crucial developmental period during which time they form their first social bonds. Puppies exposed to many different people, places, animals, and environmental events during this time will be better able as adults to accept changes in their environment. This socialization process must be done gradually, and in such a way that a puppy has only positive experiences. Puppies socialized in this way will be less likely to be afraid, defensive, and aggressive. Puppies which are fearful and aggressive may need professional help.
   Dog owners should NEVER encourage aggressive behavior. When dogs are encouraged to "go get'em" or to bark and dash about in response to outside noises or the approach of a person, territorial and protective aggressive behavior may be the result.
   Intact males dogs are more likely to display dominance, territorial, and protective aggressive behavior than are neutered males or females. Neutering a male dog will thus help to reduce the frequency of these types of aggressive behaviors. Neutering will not affect fear motivated, redirected or possessive aggression.
   A veterinarian can determine if aggressive behavior is the result of disease or illness. For a more in-depth understanding of aggressive behavior, consult a professional animal behaviorist.



		2007