Author: Gary L. Clemons DVM
I want to start by saying, much of the information I will present, has come from Karen Overall DVM’s book, Clinical Behavioral Medicine For Small Animals. Rather than trying to “reinvent the wheel”, I used the wealth of information that was available in her book. I have written articles on canine aggression, using information from my own experiences plus what others had written. Dr. Overalll graduated from the University of Pennsylvania, School of Veterinary Medicine in 1983, completed a residency in Behavioral Medicine at Penn in 1989. She is a Diplomat of the American College of Veterinary Behavior and is certified by the American Behavioral Society as an Applied Animal Behaviorist. She is currently on staff at the University of Pennsylvania, School of Veterinary Medicine where she runs the Behavioral Clinic.
Aggression is best defined within a given text as an appropriate or inappropriate threat or challenge that is ultimately resolved by combat or deference. (Overall, 1997)
It is important to realize that aggression can be an appropriate response in certain contexts. (Overall, 1997) An example is when a child is running through his own yard and a friend is chasing him. If the child is screaming, his own dog may feel he is being attacked by the other child and may go after the visiting child. In this context, the aggression may be appropriate. A dog barking at a stranger approaching his yard may be an appropriate response as well. Hopefully the dogs will be able to control their aggressive actions.
It is important to realize that dogs exhibiting inappropriate out-of-context aggression are not misbehaved or poorly behaved. They are clinically abnormal and must be regarded as such. (Overall, 1997)
For the dog’s behavior to improve, it is critical that the dog not be “provoked”. To do so, even unintentionally, only reinforces the inappropriate, undesirable, and perhaps dangerous behavior. (Overall, 1997)
Dominance aggression usually develops at social maturity, usually dogs 18-24 months of age. Signs of interaction can include standing very rigid, up on the toes, growling, hair up on the back, ears erect or slightly back, snarling, baring the teeth and wagging of the tail. If a dog is encountered showing any of these signs, it is also willing to interact in an aggressive manner if provoked. Simply staring at or reaching for these animals may be enough cause for the dog to attack.
Dr. Overall lists 6 factors to evaluate in canine communication that may forewarn you about an impending aggressive encounter:
It is important to reemphasize that most aggressive dogs are clinically behaviorally abnormal and aggressive dogs should not be be described as viscious. Viscious is a term applied to humans which connotes an underlying emotional state that does not correlate well with canine behavior. “Dangerous” is a better description. (Overall, 1997)
In the United States more than 1 million people per year report dog bites and as many as 10 people die each year from these bites. Half of these bites leave scars and up to 30% result in time lost from work or school. Most bites are inflicted by pet animals. In one study involving 3200 children 4 to 18 years of age, 45% reported having been bitten by a dog. (Jones & Beck, 1984) Because of children’s height, bites commonly occur in the upper extremities, shoulders, head, and neck regions. (Poderscek & Blackshaw, 1991) Seventy- percent of dog bite related fatalities occur in children younger than age 10 and 10.2% occur in individuals older than 69 years of age. (Sacks et. al.,1989) Of 96 cases of dog bites reported in the Veterinary Record (1991), 85% occurred in the owner’s home, 62% represented adults bitten by their own animals, 75% of bites to children occurred when they visited neighbor or friends, 54% involved bites in which the victim was younger than 15 years of age and male dogs were responsible for most bites. Sustained attacks were more commonly reported for large-breed dogs such as German shepherds, Dobermans or Staffordshire bull terriers.
Most dog bites to children occur in the summer, most bites occur on weekends, and most often late afternoon or early evening. (Kizer, 1979) Most children and dogs are outdoors and active during these periods. (Clifford et. al., 1983)
When the human participants are children, they may be uncoordinated and appear unpredictable because of their sudden shifts in posture and vocal range when excited. Some behaviors and some intensities of behaviors in young children can frighten dogs and make them feel threatened. Other behaviors like shrill squealing, could be misinterpreted by the dog as sounds and signals given by a prey item. Children can be unpredictable, dogs can be unpredictable, and the interaction can be toxic. (Overall, 1997)
Breeds that were overrepresented at the Behavioral Clinic at VHP, were Chows, Cocker spaniels, Dalmatians, and English Springer Spaniels. Borchelt (1983), found that purebred dogs were overrepresented when compared with mixed breeds only for one form of aggression: dominance aggression.
Physical factors that may affect the amount of damage caused by an aggressive dog include size (both mass and height), age (younger dogs rare more energetic and less constrained by physical disability), jaw structure and physique. Rottweilers and Doberman pinschers, dogs with nasty reputations, are responsible for a small percentage of injuries requiring plastic surgery, whereas sustained attacks are most common in German shepherd, Doberman pinschers and Staffordshire bull terriers. (Vet Record, 1991)
Although male dogs are involved more often in aggression problems, neutering has little effect on this problem. Testosterone acts as a behavior modulator that makes dogs react more intensely. When an intact dog decides to react to something, he reacts more quickly, with greater intensity, and for a longer period of time. If the dog is reacting to a strange person or another dog, he will be quicker to bark, growl, or bite, and will continue for longer than a neutered male. (Overall, 1997) Castration decreases aggression in 62 % of interdog aggression between male dogs. (Hopkins et. al., 1976)
A re-analysis of Borchelt’s (1983) data indicates the following.
Dominance aggression : Intact males represented more frequently than neutered males or females
Fear aggression: Intact females represented more frequently then intact males
Protective aggression: Neutered males represented more commonly than neutered females
Possessive aggression: Intact males represented more frequently than intact females and castrated males represented more frequently than intact females (Overall, 1997)
A very interesting observation was made by Dr. Overall in a preliminary study examining the effects of neutering on the behavior of dogs younger than 6 months of age and 12 months of age or older, one group stood out. Females younger than 6 months of age who were already showing signs of dominance aggression became more aggressive after ovariohysterectomy. This information, if reproduced by others, may be important as far as evaluating which animals are adoptable and which are not.
It is imperative to start trying to prevent aggressive behavior before it begins, when a puppy is very young. Pups go through a very critical socialization period between 8 and 16 weeks of age. During this time all pups should be exposed to people and children of all ages, exposed to other dogs, and taken away from their homes to new environments.
It is a well known fact that the ideal time to adopt a puppy is 7 1/2 to 8 weeks of age. If a pup is being handled by a lot of different people, of all ages, and exposed to other dogs, the age of adoption is not quite as critical. Pups that are bottle fed, away from their mothers, can develop inappropriate social behavior toward other dogs. Pups raised in kennels past 3-4 months of age and not exposed to new environments, people or other dogs, can become very fearful when adopted or sold.
It is very important that dog owners adopt pups at the correct age and begin early training and socialization. They must teach the pup to defer to them for everything. They must discourage rough aggressive play such as hand-fighting, and in many cases, tug of war games. If played, the human must always win and the game must stop if the pup becomes too aggressive. All dogs must be taught early commands, especially sit and down. Then it must earn everything it gets. It must sit before it eats, goes out the door, plays, or receives attention, preferably from all members of the household, especially children. No pup showing aggressive signs, should be allowed on the furniture or in the bed, because this elevates its place in the social order. Owners should be able to hand feed and take favored objects away from pups. This 8 to 16 week age is extremely critical. If a pup has to earn its favors from everyone, it soon learns it must depend on people for food, shelter and play.
Treating aggressive dogs is possible but clients must understand there is rarely ever a cure, but the condition can usually be controlled. At VHUP, client compliance was the single best determinant of success. (Overall, 1997)
Clients must avoid situations or circumstances that are known to precipitate the specific aggression. Any time the animal executes an inappropriate behavioral response, it learns from that response. It is critical that the dog not be allowed any reinforcement. Reinforcement allows learning of inappropriate behaviors. (Overall, 1997)
Owners must be able to monitor the early warning signs and startle or correct the animal prior to the development of the specific behavior. If the behavior has already started, it must be interrupted within 30-60 seconds of the start of the behavior. (Voith & Marder, 1988)
Sitting and staying are natural dog behaviors that correspond to lower positions in the social hierarchy and serve as a time out. It teaches the dog that the owner is the leader and deserving of deferential behavior, and all cues must be taken from the owner. This is very important because at the crux of aggressive problems is the fact that these dogs are abnormal; they are incapable of making appropriate, in-context distinctions. These dogs exhibit inappropriate, out-of-context behavior. Early intervention must be aimed at achieving excellent voice control and teaching the dog to make better context distinctions by taking cues from the owner. (Overall, 1997)
Dogs exhibiting dominance aggression challenge and threaten their owners or other humans for control by staring, barking, or growling when given commands. They lean on their owners, growling or biting when disturbed while sleeping or stepped over, or frequently have the “last word” when verbally corrected, and when physically punished, become more aggressive. Absolutely no physical punishment must be used. (Overall, 1997)
It is very important for all dogs to receive some sort of obedience training. Early testing of pups may help with early recognition of future behavioral problems. It must be emphasized that most dogs with behavioral problems are not just misbehaving, they are not normal, and to treat them as normal, but misbehaving animals and expect normal responses to ever intensifying corrections, is dangerous to the pet and the client alike. (Overall, 1997) It is never appropriate to recommend to an owner to hang a dog from a choker collar to subdue aggression. (Myles, 1991)
There are many different classifications of aggression. I will use the classifications Dr. Overall uses in her book. They are maternal, play, fear, pain, territorial, protective, interdog, redirected, food-related, possessive, predatory dominance and idiopathic aggression. It is important to realize that some dogs can exhibit several different types of aggression.
Dominance aggression is the number one canine behavioral problem. Dominance is not defined as aggression on the part of the dominant” animal, but rather as the withdrawal of the “subordinate”. (Gartlan, 1968; Rowell, 1972, 1974) The behavior of the lower status individuals, not the higher ranking one, is what determines the relative heirachial rank. Truly dominant dogs will tolerate lesser ranking dogs, as long as they defer to the dominant dog. Through the use of body language, dogs are able to communicate and avoid actual combat. A stare, a slightly raised lip, or raised hackles, are usually enough to make a lower ranking dog back down. Whenever two dogs feel they have equal status, a fight may occur.
Dominance aggression is an abnormal, inappropriate, out-of-context aggression, that is manifested by dogs toward people when the “resource” is access to control. It is likely that dominance aggression, like most other diagnosis of aggression, are manifestations of an underlying anxiety disorder. When a dog is pathologically anxious about its relative role in the social environment, the default rule is either to take control or test the social environment to determine whether it can challenge for control. When this behavior pattern is associated with people, it is called dominance aggression. When it is associated with dogs, it represents one manifestation of interdog aggression.
Dominance aggression is about the concept of control. The dog is faced with a challenge about control in any punishment situation. For a dog that already challenges a leadership role, the only choice is to return any challenge in kind. (Overall, 1997) When dogs are anxious and uncertain about their role in the social hierarchy, they will often make demands and respond accordingly to the owners reactions. If the owner backs down, the dogs aggressive tendencies are reinforced. Treatment requires that the dog defers to the people.
Owners do not often recognize the “pushy” behavior exhibited by dogs. The subtle growl when pushed off the couch, the paws on the shoulders or talking back. The dog thinks the owner is deferring to them. The following tables, Box 6-8 and 6-9, from Dr. Overall’s book, lists human behaviors that may elicit aggressive behavior and canine behaviors that are a part of dominance aggression.
Dr. Overall divides dominant aggressive dogs into two broad groups. Those that have no doubt that they are in control and those that are unsure of their social role and use their aggressive behavior to define their social boundaries and roles.
A majority of the dominant aggressive dogs are males and castration has limited effect toward treating these dogs. It is still recommended, if for no other reason, than to keep them from reproducing. Intact male dogs are more reactive and react more quickly, react at a more intense level, and stay reactive longer. (Overall, 1997)
These dogs must be taught to defer to their owners for everything and they must be asked to participate in any activity. They must wait and perform some command before they are allowed to eat, play, go through doors, be groomed or before receiving any attention. They must earn everything they get. Eventually, through much deference, most dogs will learn to become subordinate. Some dogs will not, and for every dog there must be a stopping point. For some dogs, euthanasia is the only solution.
The dog owning public has much to learn about dog behavior, as do many veterinarians and dog trainers. Fortunately, animal behavior courses are becoming very popular. Videos, such as Ian Dunbar’s “Sirius Puppy Training”, should be required viewing for everyone that gets a puppy, whether or not they have ever trained a dog. People like Dr. Karen Overall, at VHUP, by teaching veterinary students, their lectures to veterinarians, and their books, are leading the way toward making dog ownership more enjoyable and safer. People like myself must be the disciples that disseminate this information to the dog owning public, so someday, talks about canine aggression will be a thing of the past.
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