The word aggression can refer to a range of behaviors from barking and growling, snarling and snapping, to biting and attacking. Threats of aggression are one way dogs have of communicating and are often displayed as a means of avoiding outright aggression. However, a threat (growling or snapping) may escalate to outright aggression (biting) in any given situation.

Types of Aggression

FEAR-MOTIVATED AGGRESSION: Fear-motivated aggression is a defensive reaction and occurs when a dog believes he is in danger of being harmed. Remember, it is your dog’s perception of the situation, not your intent, which determines your dog’s response. For example, you may raise your arm to throw a ball, but if your dog perceives this to be a threat, he may show aggressive behaviors to protect himself from being hit.

POSSESSIVE AGGRESSION: Possessive aggression involves the defense of valuable resources. Maternal aggression is a specific type of this aggression in which mother dogs become defensive of their puppies. Resource guarding is another type of possessive aggression where dogs defend their food, toys or other valued objects, such as Kleenex stolen from the trash!

SOCIAL AGGRESSION: Animals living in groups, like dogs, establish relationships through which the individuals involved interact and live together. The roles the individuals play within the relationship can change with each new day or situation and can be affected by the presence of various resources, such as food, toys and attention from people. Social aggression can also occur when there is lack of communication within the relationship. Social aggression can be complex and not best resolved through physical force.

FRUSTRATION AGGRESSION: Some dogs, if restrained when aroused, excited or fearful can be aggressive toward the person restraining them or show aggression toward a passing person or animal. A dog being held back by the collar for instance may turn and bite the hand on the collar. A dog may also show aggression toward a person walking by them when they are in a cage, crate, car or when on a leash.

REDIRECTED AGGRESSION is a type of frustration aggression. If a dog is aroused into an aggressive response by a person or animal, he may redirect this aggression onto someone nearby. Owners for instance are often bitten when they try to intervene in a fight between two family dogs. Another example occurs when there are two family dogs who become excited when a person or dog passes by the yard. The two dogs, which are confined behind the fence, then turn and attack each other because the fence prevented them from getting to the intruder.

PAIN-ELICITED AGGRESSION: An otherwise friendly and social dog may also bite or snap if touched when he is in pain. You may be treating him or attempting to help him, but he perceives any touch from you as potentially painful and snaps or bites to make you go away. If you are working with a dog in pain, it is a good precaution to muzzle the dog. Some training tools that inflict pain, such as prong collars, may provoke a dog to pain-elicited aggression. We do not recommend using tools that cause pain or fear.

PREDATION is usually considered to be a unique kind of aggressive behavior because it is motivated by the intent to obtain food, and not primarily by the intent to harm or intimidate. Some breeds have high incidences of this based off of breed characteristics.

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 low, a dog will be more likely to bite. Raising the threshold makes a dog less likely to respond aggressively. This threshold can be raised using behavior modification techniques. How easily the 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 dogs can be potentially dangerous, and should be done only by, or under the guidance of, an experienced animal behavior professional who understands animal learning theory and behavior.

What You Can Do

  • First check with your veterinarian to rule out medical causes for the aggressive behavior.
  • Seek professional help. An aggression problem will not go away by itself. Working with aggression problems requires in-home help from an animal behavior specialist.
  • Take precautions. Your first priority is to keep everyone safe. Supervise, confine and/or restrict your dog’s activities until you can obtain professional help. You are liable for your dog’s behavior. If you must take your dog out in public, consider a cage-type muzzle as a temporary precaution, and keep in mind that some dogs can get a muzzle off.
  • Avoid exposing your dog to situations where he is more likely to show aggression. You may need to keep him confined to a safe room and limit his people-contact.
  • If your dog is possessive of food, treats, or a certain place, restrict access to those items or areas. If he gets a hold of an item, trade him for something better. For example, if he steals your shoe, trade him the shoe for a piece of chicken.
  • Spay or neuter your dog.

What Not to Do

  • Punishment will not help and, in fact, will make the problem worse. If the aggression is motivated by fear, punishment will make your dog more fearful, and therefore more aggressive. Attempting to punish or physically dominate an aggressive dog may cause him to escalate his behavior and is likely to result in a bite or severe attack.
  • Do not encourage aggressive behavior. When dogs are encouraged to “go get ‘em” or to bark and dash about in response to outside noises or at the approach of a person, aggressive behavior may be the result.