What is aggression?
Aggression may be defined as any threatening or harmful behavior directed toward another individual or group. Dogs can use their body language to communicate aggressive intent without causing physical harm. It is often considered undesirable or problematic when dogs direct aggressive behaviors toward people or animals.
Aggressive displays can range from subtle postures, such as staring or leaning forward, to more obvious postures, such as growling, barking, snarling, snapping, lunging forward, or biting.
Bites are most likely to occur when a dog’s arousal level is high, when a dog is physically ill or in pain, or when prior lower-level displays of discomfort have been ignored.
Aggression can be a normal form of communication in dogs and may be used to avoid the further escalation of conflict. A dog may react aggressively to displace another individual, to gain access to a resource, or to maintain a safe space or distance from a perceived threat.
Are there different kinds of aggression?
There are many different categories or types of canine aggression. Aggression may be categorized by the dog’s motivation, the context in which the behavior occurs, or the intended target.
Territorial Aggression: Aggression directed toward a person or animal that enters or approaches an area that the dog perceives as their territory. The area is most often the caregiver’s home or property, or a small space such as a vehicle or crate.
Possessive Aggression: Aggression exhibited when a person or animal approaches while the dog is in possession of something they covet, such as food or a toy. The behavior is often called resource guarding, as coveted possessions are often basic resources. Possessive aggression can include resting places and valuable social companions.
Maternal: Aggression exhibited by a female dog when her puppies are approached.
Protective Aggression: Aggression directed toward a person or animal that threatens a valuable social companion.
Pain-Related or Irritable Aggression: Aggression directed toward a person or animal whose behavior causes or threatens to cause physical pain or emotional discomfort.
Redirected Aggression: Aggression directed toward a person or animal that is not the initial target for the emotional response. Redirected aggression is frustration-based and occurs when a dog cannot reach the initial target.
Social Conflict-Related Aggression: Aggression that is motivated by internal conflict during social interaction. Social conflict-related aggression is typically directed toward a familiar person or animal whose behavior triggers frustration and/or anxiety.
Inter-Male or Inter-Female Aggression: Aggression between two male dogs, particularly when they are competing for a female dog, or between two female dogs, particularly when a younger dog reaches social maturity.
Disease-Related Aggression: Aggression caused by a primary disease such as a lesion in the brain or secondary to a physical disease, particularly when the illness includes pain or discomfort.
Fear- or Anxiety-Related Aggression. Aggression directed toward a person or animal whose behavior toward the dog causes it to fear for its safety. A dog may be frightened if they feel cornered or trapped, even if the person approaching has friendly intentions.
Predatory Behavior: Predatory behavior is not considered true aggression, as it is exhibited without emotion. Vocalization and other threatening signals are absent. Hunting prey is a species-typical behavior motivated by the drive to capture-kill-consume the target.
How do dogs show fear- or anxiety-related aggression?
Fear- or anxiety-related aggression is perhaps the most common form of aggression in dogs. Most types of aggression listed above likely have a fear or anxiety component, except for predatory behavior and disease-related aggression.
Fearful dogs often initially exhibit defensive postures, such as barking while backing away or crouching. These signals are intended to create a space or distance from the perceived threat. Yet over time, a fearful dog may also begin to display more offensive postures, such as lunging forward toward the target. This change often occurs after initial postures have either been ineffective, meaning that the scary thing continues to approach.
"Fear- or anxiety-related aggression is perhaps the most common form of aggression in dogs."
Offensive behaviors may also develop if fearful dogs are scolded for their attempts to communicate their fear. For example, if a dog is scolded for barking and backing away, the dog may become confused and more frightened by the situation. Instead of refraining from barking, the dog may lunge forward. While displays of offensive or defensive aggression look different, the primary motivations for the behavior are the same: fear and the desire to drive the stimulus go away.
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?
Aggression is a normal form of canine communication. For example, it is common for dogs to bark when they notice an intruder near the property. It is also normal for a dog to attempt to maintain resources that are important for survival, such as food and a comfortable resting place. An individual dog’s behavioral tendencies are shaped by the dog’s genetic makeup, their health and diet, the health and behavior of their mother, and all their life experiences.
"A dog that experiences fear, anxiety, frustration, or pain may be less tolerant of perceived threats and may respond with an aggressive display."
Most of the time, dogs use safe, inhibited aggressive displays to communicate. They may stare, stiffen, bark, or growl. Sometimes, aggression is less inhibited and can escalate to snaps and bites. A dog that experiences fear, anxiety, frustration, or pain may be less tolerant of perceived threats and may respond with an aggressive display. Dogs that have experienced confrontational or correction-based training methods and dogs that are punished for using low-level aggressive displays may be at risk of behaving aggressively during social interactions.
Aggression may be seen in dogs of any age, including young puppies. If you notice any aggressive postures, consult with your veterinarian immediately. Regardless of the age at which you notice aggressive behavior, it is important to address the underlying emotional factors. Do not confront or scold your dog, as your dog is likely to become frightened or frustrated.
What are the warning signs of aggression?
Though aggression can be normal, it is important to reduce the risk of your dog biting another person or dog. It is helpful to identify the warning signs that predict a bite might occur.
Many dogs use conflict-appeasing signals, sometimes called calming signals, to defuse social conflict and avoid physical confrontation. Any of the following signs may be displayed. The signals are listed from low to high intensity:
- Avoiding eye contact by squinting, turning the head, or turning the body away from the threat
- Yawning or licking the lips
- Pinning or flattening the ears tightly to the head
- Crouching, lowering the body, or tucking the tail under the body
- Stiffening or freezing
- Growling
- Snapping
- Biting
Should I be concerned about displays of aggression by my dog?
Yes, aggressive behavior means there could be a bite. It is important to learn the reason for your dog’s aggressive displays. Aggression may be caused by pain, by infectious diseases such as rabies, or by non-infectious diseases such as those affecting the nervous system, so it is important for your veterinarian to examine your dog carefully. If no physical disease is present, then a veterinary behaviorist should assess your dog for underlying behavioral illnesses that could trigger aggression. The sooner you seek treatment, the better the chance for improvement.
Is there treatment for aggression in dogs?
Yes, there is treatment for aggression in dogs, but the potential for aggressive behavior may not be fully eliminated or “cured”. Aggressive behavior can often be reduced in frequency or intensity, but long-term management is typically needed to assure safety.
The treatment plan will be based on the underlying motivation or type(s) of aggression exhibited. Your veterinarian will diagnose and treat the underlying physical illnesses. A board-certified veterinary behaviorist will work with your veterinarian to ensure that your dog’s physical and behavioral illnesses are addressed appropriately. Treatment always includes behavioral and environmental modification. In some cases, psychotropic medications are added to the treatment plan.
The treatment of aggression may be challenging.
