This handout reviews the problem of interdog aggression and offers suggestion for dealing with this situation. It is important that you are in communication with your veterinarian and that your dogs have been examined and screened for any new medical or physical issues that could contribute to the behavior problem.
What should I do when one of my dogs challenges another?
Aggression between household dogs can be difficult to treat. You will need to identify the situations in which aggression arises and ensure that you are not encouraging a more subordinate dog to challenge the more confident dog. Similarly, you would not want to encourage the dog that is less interested in a resource to challenge the one with a higher motivation to hold on to that resource. It is critical that you never come to the aid of the subordinate against the more confident. If left alone, the dogs will often use posturing and threats to end encounters without injury. If one dog backs down, the problem may be resolved. However, when both dogs are equally motivated to challenge, assert and posture, fighting will usually result.
A common owner error is the desire to make life “fair.” This often results in owners allowing subordinate dogs or ones who would normally have less interest to have access to resources, such as attention, treats, toys, or entry into territory that they would not normally try to obtain in the presence of the other dog, if they were not encouraged by their owners. Often the subordinate dog does not behave in a manner that would challenge the confident dog when no one is around to “protect” it. If you encourage or come to the aid of the subordinate dog rather than discourage its behavior, you may increase the chances that the more assertive dog will challenge it. If you then punish the assertive dog for aggression, the subordinate dog might be encouraged to repeat the behavior. In addition, the use of any discipline or punishment techniques might lead to increased anxiety when the dogs get close to each other. In many households, there is no fighting when the owners are gone, which is likely an indication that the owners interactions are in some way encouraging the dogs to interact in a way that they would not when the owners are away. Whether the owner’s actions are in some way encouraging the behaviors that lead to fights, or whether the owners are responding inappropriately to one or both of the pet’s actions, needs to be determined.
Another potential problem may occur when the relationship between individuals is context dependent. In other words, one dog is more motivated to receive owner attention while the other defers. However, the dog more motivated for attention may be the one that is less motivated by food and will therefore avoid and defer during feeding.
Before treatment can begin it must be determined if either dog is using appropriate canine social communication skills. If one dog is not responding appropriately to the deference and appeasing signals of the other dog, is attacking over low-level threats or does not allow any approach by the other dog without displaying aggression, then fear or anxiety are likely factors. Anxious dogs will often respond defensively and are not able to accurately assess the situation and choose an appropriate response.
Can social aggression always be corrected?
Although dogs are social and live in groups, in a free ranging situation they would choose which group to live in and leave those where they are not welcome. Most people could not live together harmoniously in a small group arrangement with individuals someone else selects; we should admire our dogs flexibility that they are willing to let us pick their friends most of the time. However, some dogs will simply never be friends. Assessing the level of the threat and the potential for safety is the first step in determining the prognosis at least in the short term. Dogs that threaten but do not cause injury may learn to communicate in a way that avoids any further escalation to aggression, provided the owner does not intervene with normal communication and learning. On the other hand in some cases, even if the situations in which aggression might arise are infrequent if they cannot be predicted and prevented or if they lead to injury, (perhaps due to size or health differences or overly intensive responses on behalf of one or both pets) then the situation may be too dangerous to allow the dogs to be housed together. Identifying specific triggers or situations in which problems might arise, can provide a viable opportunity to be able to prevent and possibly improve the aggression. If predicting and preventing potential aggression is not practical, training and owner supervision does not ensure safety, problems cannot be improved with behavioral management, training and perhaps drugs or preventive products and preventive measures such as muzzles, crates or head halters cannot be effectively used to insure safety, then alternative housing may be required for one or more of the dogs.
Should I punish my dogs when they are challenging each other?
Punishment should be avoided. The dog-dog relationship will not be improved if you scold, punish or hold down a dog as punishment; in fact you may make it worse by punishing the dog for signaling and communicating their aggressive intentions. Good communication between the dogs is actually helpful to avoid serious fights. If the dogs are punished for communication such as growling, snarling, snapping or lip lifting then these important canine communications may be suppressed. Effective communication between the dogs is the key to harmony. Canine Communication – Interpreting Dog Language.
Instead, if you can see that the dogs are about to fight, the dogs should be called, redirected or encouraged to do something else. Ideally the assertive dog is called to come, sit and stay. This must be taught and rewarded in a positive reinforcement program. If you call or punish harshly or sternly then you will suppress the dogs communication when you are around. If the assertive dog doesn’t obey, then you need to refresh his obedience commands in a separate occasion. This dog may need to drag a leash attached to a head halter device so the aggressive events may be managed safely without escalation of human emotion adding to the aggression (see Head Halter Training – Synopsis).
The submissive dog should be observed for willingness to retreat, move away, look away and avoid confrontation. This is normal canine deference and as much as it may seem unfair to people, it is critical for a harmonious relationship among a group of dogs. Teach the submissive dog to retreat on command – teach a “go to” command and practice this other times. If the submissive dogs wants to avoid confrontation but isn’t sure how, then putting a retreat command on cue can help this dog learn how to avoid an aggressive confrontation. Avoid calling the submissive dog to come to you or retreat in such a way that she must walk toward the more confident dog as this may be perceived as a confrontation. If the submissive dog ignores your commands, observe the situation closely as she may be deferring to the more confident dog. Avoid forcing the submissive dog to follow your commands which make her confront the more confident dog. For example, your more confident dog is standing outside the door while you are letting the more submissive dog outside. You tell her to out, she looks past you at the more confident dog who is quietly, standing erect and she elects to ignore you rather than confront that dog. Probably a smart choice as her ability to read the other dog’s body language likely exceeds yours. Forcing her to go on outside may result in dog fights, if not immediately, eventually. So instead, go out to the more confident dog and ask him to follow a series of commands gradually moving him away from the door. Ask him to stay. Go back and call out to the submissive dog who will likely follow your commands readily now.
How can I treat this problem?
Although the relationship between the two dogs must be dealt with, the first step is for the owner to gain complete control over both dogs. This should be accomplished through (a)verbal control with reward based training so that each dog can settle on command both in position (sit/focus) and on location (crate/mat) (see Teaching Calm – Settle and Relaxation Training), (b) a command-response program in which the owner controls access to all resources and all social interactions and ensures calm and deferment behavior before these are received (see Learn to Earn – Predictable Rewards), and (c) a daily routine that provides sufficient training, play and exercise sessions alternating with rest times where the dog can nap or play with its own toys (preferably in its own bed area) and (d) physical control and safety, preferably with a leash and head halter. The command-response program serves to eliminate all attention on demand. If your dogs learn that all rewards are provided only when you choose, this will likely reduce or eliminate some of those situations where challenges might occur. The leash and head halter provides a means of effective control as well as a way of separating the dogs if needed. With control of the head and mouth, aggressive threats can be curtailed and either dog can be placed in a controlled position, by pulling up on the leash, closing the mouth, looking the dog in the eyes, or pulling the head sideways so that the dog’s gaze is averted. Muzzles might be another alternative to keep people and dogs safe.
All situations in which aggression might arise must be identified and entirely avoided or prevented until such time as the owner has safe control for introduction. Identifying all stimuli for aggression is also essential in making a diagnosis, determining the prognosis and developing a treatment plan that deals with the specifics of the household.
Once you have gained sufficient control over both dogs, and have identified the more confident, assertive dog, you will need to deal with the circumstances that might elicit aggression. First, determine whether the responses of one or both dogs are appropriate or inappropriate. In those cases where the behavior appears to be related to resource value challenges, the approach would be to support the dog that is likely to be more confident dog in the relationship by discouraging challenges and approaches of the more subordinate that might progress to aggression. With the assistance of a behaviorist and a detailed description and/or video of the events, it should be possible to determine which dog is more able to take or maintain control. One option is to support the dog that has been in the household the longest; usually this is the oldest dog. Another is to identify the confident dog based on how the dogs interact, in other words, who threatens and who defers. In some cases the dog that is chosen could be the maturing younger, more physically capable dog, if this dog has been trying to assume control and shows appropriate responses. Care must be exercised to watch for dogs that try to take control but do not allow other dogs any status or are inconsistent in the application of threats (i.e., the bully). Dogs that are unable to read social communication signals appropriately (such as those that are older, unhealthy or infirm) also should not be chosen as the leader dog.
Ideally, the program should be passive and the dogs should be encouraged and reinforced for proper responses and problem free interactions. For example, if the more confident dog approaches or challenges the subordinate dog and the subordinate dog assumes a subordinate posture, the owners are not to intervene as long as the confident dog ceases the challenge. However, if dogs were able to work things out on their own, you would not likely be reviewing this handout. Therefore, every situation in which the dogs might become aggressive should be prevented or placed under owner control and supervision. Greetings should be low key, and both dogs should be ignored. If greetings are a problem, keep the dogs separate when you are out. Food, treats, toys, affection and resting places, can all be sources of competition and should be entirely under owner control. Movement through tight spaces must be avoided or controlled as there is more opportunity for confrontation and little area for the submissive dog to avoid or defer.
Although the goal is to prevent problems so that there is no further injury or occurrence, you will also want to work toward improving those situations in which the aggression might arise. If the specific times, places and stimuli that lead to aggression are predictable it should be possible to set up situations to teach the subordinate to defer (with the aid of verbal commands, such as down-settle or go to your mat, and a leash and head halter to ensure safe, immediate and effective control). Often your actions are inadvertently encouraging the subordinate dog to challenge to the more assertive. This might include providing attention, affection, play, food, toys or even a privileged sleeping location by your side. In principle, if any of these lead to problems, they should be provided to the more confident dog first and the subordinate encouraged to wait its turn. Often the submissive dog is willing to wait; it is often the people that want life to be fair so they coax and encourage a submissive dog to approach which only escalates the perceived threat by the other dog. Once you are finished, the more confident dog can be asked to do a down-settle while you provide similar resources to the other dog. If the confident dog begins to display threats or anxiety while you attend to the more subordinate, you will need to teach the assertive dog to settle when interacting with the subordinate (desensitize, counter-condition) and you should ask the assertive dog to down stay further away or behind a baby gate. This might require two people and the use of a leash and head halter to ensure success. In the interim, removing the more assertive dog from the sight and sounds of the interaction might be best (e.g., outside, crating).
If problems arise during walks, it is usually best to start with two people walking the dogs (each person controls one dog) and not to allow them to forge in front of each other. Both should learn to walk on loose leash with no anxiety by the owner’s side. During feeding or when giving treats or toys keep the dogs at a distance, far enough apart that they do not show aggression. Slowly the dishes, toys or treats can be moved closer together as long as the dogs remain focused on their own items. Dogs can be taught to settle when they are in the same area or room with a down/stay and rewards. However, until they can be effectively trained another alternative is to attach their leashes to large pieces of furniture.
Social play should be allowed to continue as long as it does not escalate to aggression. If aggression is a possibility during play (or any other social interaction), you must be able to identify the signals and actions that indicate that aggression is likely to emerge so that you can stop the interaction. Generally starting with the subordinate, get each dog to settle before allowing further interactions to continue. This can be accomplished by using a settle command (with head halter if needed). However, if the more assertive dog increases its attacks on the subordinate as you begin to intervene, you may have to focus on getting the assertive dog to settle first (giving it preferential attention) or you may need more people to break up the play. During daily interactions, you should be cognizant of what interactions could possibly lead to fights or challenges. In any situations where problems might arise, allow priority to the confident dog, to approach, receive food or owner attention and affection. If you are petting the confident dog and the subordinate dog approaches, make it wait. If the confident dog signals to the more submissive dog to wait (by snarling, lip lifting, glaring or becoming erect) and the more submissive dog defers then you should not interfere!! Most people find this difficult but if you punish the confident dog and call the submissive dog to you (which is our human, life should be fair, response) then you will be inadvertently teaching the confident dog to be more aggressive and the subordinate dog to ignore his communication signals. If the dogs are likely to fight when you are away or at homecomings, separate the dogs whenever you are not available to supervise. Basket muzzles could be left on each dog to increase safety while the dogs are together making sure that the dogs do not become overheated while wearing a muzzle.
What if neither dog will defer or submit?
On some occasions, neither dog is willing to be subordinate, or there may be a shift in hierarchy from situation to situation. You will need to supervise the dogs in these situations and be able to recognize canine body language and low-level threats such as eye contact, snarls or low growls (see Dominance, Alpha, and Pack Leadership – What Does It Really Mean? and Canine Communication – Interpreting Dog Language).
Keep records of threats, attacks, or tension-producing situations. Try to determine if the problem is related to a specific resource such as feeding or a play toy or to a specific event such as greeting so that steps can be taken to separate the dogs at these times to avoid any possibility of recurrence. An owner must have excellent control over both dogs in order to succeed. To facilitate treatment, decrease the chances of injuries and increase owner control, a remote leash and head halter can be left attached to one or both dogs when they are together (under the owner’s supervision). In other cases, basket muzzles may provide more safety and allow owners to work with
If there are abnormal responses to social signaling then these cases may have a very poor prognosis and be most likely to escalate to serious injury. This might be the case if the dog displaying confident signals continues to attack in the face of appropriate deference and subordinate behavior, or if the more subordinate dog displays excessively fearful or defensive aggression when confronted by normal social or distance increasing signaling from another dog. These cases require close and careful supervision and may have a much poorer prognosis. Drug therapy might help to control anxiety and impulsivity.
If aggression is redirected or caused by another anxiety producing situation such as separation anxiety or social changes within the home, those need to be addressed as well or the problem will not change.
How should I break up fighting between dogs?
This can be a dangerous situation for people and dogs alike. Owners usually try to reach for the collar of the fighting dogs, or if one is small, pick it up. This can result in severe owner injury if the fighting is very intense. If both are wearing leashes, they can usually be pulled apart. A leash attached to a head halter is preferable since it would then be possible to turn the head and close the mouth. One of the greatest challenges is to determine whether one or both dogs are responding inappropriately. If one of the dogs is showing deference signals and subordinate posturing and the other continues to fight then, in this example, the focus of control (i.e., leash and head halter) might need to be on the more confident dog. If all else fails, you might be able to break up the fight with a water rifle, citronella spray, broom or another distraction (such as pepper spray or a fire extinguisher). Reaching for the dog is usually the worst thing to do, as you could be injured (either accidentally or intentionally). Picking up the dogs by their hind legs and walking backwards may allow separation of the dogs without owner injury.
“When people intervene in dogfights, redirected aggression is possible.”
Aggression (growl, snarl or bite) can be redirected to a person, animal or object other than that which evoked the aggression. If during the course of a dogfight, you pick up one of the dogs, the other may continue to attack and direct it at you.
This client information sheet is based on material written by: Debra Horwitz, DVM, DACVB & Gary Landsberg, DVM, DACVB, DECAWBM
© Copyright 2012 LifeLearn Inc. Used and/or modified with permission under license.