Aggression in Dogs

What is aggression?

Aggression may be defined as any threat or harmful behavior directed toward another individual or group. It may be displayed as an intent to avoid the further escalation of conflict, as a method to displace another individual or group, or with the intent to cause physical or emotional harm to another individual.

Aggression in dogs commonly includes body language or threat displays such as a hard stare, growling, barking, snarling, lunging, snapping, and/or biting.

Aggression can be a normal form of communication in dogs, yet the display of aggression toward a person or animal is often considered undesirable or problematic.

Most canine aggression is affective or emotionally (fear and/or anxiety) motivated in the brain, yet predatory aggression is motivated by the appetite center of the brain. With predatory aggression, the animal is not afraid or anxious and aggression is displayed with the intent to decrease the distance and capture, kill, and consume prey.

What are the different kinds of aggression?

There are many different categories or types of canine aggression. Aggression may be categorized by the dog’s motivation for aggressive behavior, the context in which the behavior occurs, or the intended target of aggression. Here are examples of some common types of aggression.

Territorial Aggression. Aggression directed toward a person or animal that enters or approaches the dog’s perceived territory, which is usually the owner’s home or property.

Possessive Aggression. Aggression, sometimes called resource guarding, that is directed toward a person or animal when the dog feels threatened that the person or animal will take away valued resources, which are usually food or toys.

Maternal or Protective Aggression. Aggression directed toward a person or animal by typically a female dog protecting her offspring or puppies.

Pain-Related or Irritable Aggression. Aggression directed toward a person or animal which is motivated by pain or discomfort.

Predatory Aggression. Aggression directed toward typically another animal, yet occasionally a person, which is motivated by the desire to hunt, capture, kill, and consume species viewed as prey. Predatory aggression is typically silent or absent of vocalizations and the bite is often damaging or uninhibited.

Frustration or Redirected Aggression. Aggression incidental to another form of aggression or emotional arousal. It occurs when a dog cannot reach the target of its aggression or arousal and out of frustration changes its focus to another object, person, or other animal.

Social Conflict-Related Aggression. Aggression typically directed toward a familiar person or animal which is motivated by internal conflict and displayed in contexts of social interactions.

Sexual Aggression. Aggression directed toward another male or female dog associated with mating behavior, when male dogs compete for a female, or a female fights for access to a male.

Disease-Related Aggression. Aggression directed toward a person or animal may be associated with infectious or non-infectious disease.

Fear- or Anxiety-Related Aggression. Aggression directed toward a person or animal which is motivated by a dog that is feeling afraid, which may occur if approached, cornered or trapped, or if the animal is anxious about an uncertain or unpleasant outcome.

What are the manifestations of fear and/or anxiety related aggression?

Fear or anxiety related aggression is perhaps the most common form of aggression in dogs. In reality most types of aggression listed above, except for predatory and disease related aggression, likely have a fear or anxiety component. Fear- or anxiety-related aggression may be confusing as the dog might display defensive or offensive body language.

Early manifestations of fear related aggression are typically defensive, displayed to increase the distance between the perceived threat, or communicate ‘stay away’, yet aggression may become more offensive through learning. Aggression is offensive when displayed while closing the distance to the perceived threat. However, even though the displays of offensive or defensive aggression look different, fear and making the stimulus go away are still the primary motivation for the behavior.

Fear- and anxiety-related aggression are commonly manifested in the veterinary hospital or in situations of social approach and handling. Dogs that display aggression are not mean or bad dogs. They are simply afraid/fearful and anxious/nervous about a perceived or anticipated threat or unpleasant outcome.

Why does my dog display aggression?

Dogs may have inherited an instinct for fight or flight when faced with a threat. The display of aggression in dogs may be genetic (inherited from the dog’s parents) or a breed specific behavior. Certain breeds of dog have been selected and used to guard livestock or alert to territorial threats. Different breeds of dog have been selected to display predatory behavior. The display of aggression may be learned from previous experiences because aggression may have been successful in avoiding or preventing an unpleasant outcome.

The most common presentation of aggression is fear or anxiety motivated.

Some aggression in dogs commonly present at a young age (the first 3 to 4 months of life), yet other types of aggression are more likely to occur during adolescence or social maturity. Aggression in young puppies is most often fear- or anxiety-related. Aggression presenting during adolescence or at social maturity may be sexual, social, or related to territorial threats (which incidentally has a fear component).

What are the warning signs of aggression?

The key to dealing with aggression is recognizing the warning signs that predict a bite might occur.

Aggression is often preceded by fear or conflict appeasing signals, sometimes called calming signals. These signals are offered as communication to diffuse social conflict. Body language that may be displayed in order of the escalation of aggression are the following:

• Avoiding eye contact by squinting, turning the head, or body away from the threat
• Yawning or licking of the lips
• Pinning or flattening of the ears tightly to the head
• Crouching, lowering the body, or tucking the tail under the body
• Stiffening or freezing
• Growl
• Snap
• Bite

Should I be concerned about the display of aggression by my dog?

Yes! Aggressive behavior in dogs poses a danger to humans or other animals, with physical injury probable. Aggression may be caused by infectious diseases such as rabies or non-infectious diseases typically affecting the nervous system. If a dog is displaying aggression, its health and/or emotional welfare are likely compromised. Displays of aggressive behavior should be discussed with your dog’s veterinarian. The sooner treatment is sought, the best chance for improvement.

Is there treatment for aggression in dogs?

The treatment of aggression will depend on the cause of aggression. Aggression should first be discussed with your veterinarian regarding the most appropriate treatment. Your veterinarian may refer you to a board-certified veterinary behaviorist.

The treatment of aggression may be challenging. Aggressive behavior can often be reduced in frequency or intensity, but the display of aggressive behavior may not be 'cured'. The avoidance of situations that have induced aggression behavior should be encouraged, thereby avoiding the dog’s exposure to situations, people, or animals that trigger aggression.

Aggression in dogs is often treated with medications used in combination with behavioral and environmental modification.