Territorial Aggression Toward People in Dogs


Territorial aggression is a potentially dangerous behavior problem. In its gentlest form, dogs bark to intimidate intruders, particularly those of the same species. The barking is also intended to alert other pack members who can join in defense of the pack’s territory. If the intruder is not intimidated, warnings may escalate to include hostile posturing and lunging. If this is ineffective in deterring the visitor, an attack may ensue.

Although alarm barking can sometimes be aggravating for dog owners, neighbors, and visitors, lunging and biting are far more serious problems. Dogs with the confidence to bite strangers present a danger to any visitors to the home and a liability for the dog’s owners.

By definition, territorial aggression should be expressed toward members of the same species. Domestic dogs, however, seem to regard people as conspecifics and consequently may direct territorial aggression toward human visitors. “The territory” generally includes the house and yard, plus abutting areas (e.g. sidewalks) that the dog patrols, and family vehicles in which they ride.

When dogs display aggression to strangers only on the home property, and do not respond aggressively to strangers on neutral territory, territorial aggression is the likely diagnosis. There are two primary motivations for territorial behavior, dominance or fear/anxiety.

Territorial Aggression Fueled by Dominance

Dominant dogs have a responsibility to warn other pack members of a stranger’s approach and they do this with confidence and authority. Dogs that are overly dominant, both in absolute terms and with respect to their human family members, may provide a serious obstacle for any visitors to the home territory. Where owners have some control, they can usually reassure the dog that the person is, in fact, welcome, at which point the dog will settle down. In most cases, once a stranger has been welcomed inside the home, the dominant-territorial dog will relax and enjoy the visitor’s company.

Territorial Aggression Associated with Fear

Some dogs, notoriously those of the herding breeds, show a variation on the territorial aggression theme. Perhaps they do possess a low level of dominance and would bark anyway, but some are also insecure, anxious, or even frankly fearful. As youngsters, they may back up and bark at the sound of people approaching but, as they grow older, they find themselves more intimidating and learn that they can drive the boogeyman away. Uniformed visitors, like mail carriers, are prime targets for this learned type of aggression. The mail carrier comes, the dog barks, the mail carrier leaves, and the dog takes credit. The aggressive behavior is thus reinforced. Out on the street, these same dogs may not have the courage to intimidate their adversaries, although they might wish they had.


There are several factors that distinguish fear-related territorial aggression from dominance-driven aggression:

  • Territorial/fear aggressive dogs frequently show ambivalent body language similar to that of purely fear aggressive dogs. The body language includes: approach-avoidance behavior, tucked or semi-tucked tail, slinking gait, and an indirect approach.
  • Territorial/fear aggressive dogs do not usually settle down completely while visitors are in the home and are prone to sudden outbursts of barking or lunging and may aggress toward visitors who move suddenly, speak loudly, or get up to leave the house.
  • The bites of territorial fear aggressive dogs are usually directed towards the “nether regions” of the offender (e.g. toward the person’s buttocks, thighs, or calves) or they may simply nip, ripping clothing. The bite is usually of a hit-and-run nature – a cheap shot.
  • In a way, the only distinguishing feature between territorial fear aggression and overt fear aggression is the level of confidence that the dogs possess. Fear aggressive dogs generally have enough confidence to be aggressive to strangers on or off their own territory. Territorial/fear aggressive dogs have a lower level of confidence that permits the expression of fear aggression only on the home territory or from within the safety of the owner’s vehicle.

Management Measures

Although dominance-based territorial aggression is easier to manage than fear-based territorial aggression, both forms of territorial aggression can be addressed reasonably well by means of management measures, proper control, and containment.

Safety Precautions

Owners should keep doors secured to ensure that no one enters the property without warning. A dog that has bitten a stranger coming onto the property should not be allowed to roam unsupervised when there is the slightest chance of a stranger entering their zone. For these dogs, all off-lead exercise should be conducted in safe places, with constant supervision by an informed owner who has realistic expectations of the dog’s behavior. Electronic fences pose a particular problem for dogs with territorial aggression. The dog knows where their territorial boundaries are, but visitors do not, and they may unwittingly cross the line. In general, dogs tend to be more territorially aggressive when they are behind a fence, because a fence allows the dog to know exactly where the boundary lies, and they will patrol and protect it. Finally, owners should consider posting a “Beware of Dog” sign as a responsible reminder that a dog is on the property.

Medical Rule-outs

Consider testing the dog for medical conditions that might be contributing to increased anxiety, especially hypothyroidism. Borderline-low levels of the principal thyroid hormone may be associated with increased anxiety, and thus aggression.

Nothing in Life Is Free

Unlike humans, dogs have little sense of equality and will always aspire toward the highest possible rank within their social group. When dealing with territorially aggressive dogs, it is essential that owners establish a leadership role with respect to the dog in order to safely manage the dog’s territorial tendencies. A non-confrontational approach to leadership is the best way to accomplish this important task.

The approach we advocate is the “Nothing in Life is Free” leadership program. This requires the dog to work for anything they need or desire (food, toys, attention, access to the outdoors, etc.). In effect, they must “earn” all valued resources by first obeying a command, such as “SIT” or “DOWN.” If the dog sits automatically before the owner issues the command (i.e. anticipates the owner), the owner should issue an alternative command, before giving the dog the desired resource. The objective is to have the dog follow the owner’s directives as and when issued. If owners are consistent with this approach, the dog will learn that they must look to them to obtain anything they need or want, such as food, freedom, play, and social interaction. If the dog learns to respect their owners in this way, they will be more likely to turn to them for direction when they’re feeling challenged or fearful and will be more likely to heed directions.


Ensure that the dog receives regular daily exercise (20 to 30 minutes of aerobic exercise daily is a minimum).


Feed a healthy non-performance diet.

Obedience Training

Engage the dog in regular daily obedience training sessions to sharpen their response to one-word voice commands and increase owner leadership. One to two 5-minute sessions per day are usually sufficient. Click & treat training may facilitate training endeavors.

Head Halter

Employ a Gentle Leader® head halter to exert the optimal control of the dog in aggression-inducing situations. The head halter gently, but firmly, establishes owners’ leadership and control of their dog, as well as providing for visitors’ safety. Head halters send a biological signal of the owner’s leadership by exerting gentle pressure around the muzzle (“maternal point”) and at the nape of the neck (“leader point”). This will cause the dog to defer to his owners’ authority so that they can be introduced to people under pleasant circumstances and be rewarded for remaining calm.

Basket Muzzle

All dogs that have shown aggression to visitors in the past should be trained to wear a basket-style muzzle. A basket muzzle allows the dog to pant, drink, and accept small treats, but prevents biting. We find these muzzles to be effective and more humane than standard muzzles. Once trained to the muzzle, the territorially aggressive dog can be required to wear the muzzle in any especially challenging situation.

The approach to controlling fear-based territorial aggression is more problematic. The key to the entire program is desensitization to approaching strangers, along with counterconditioning to alter the dog’s associations and behavior during progressive, planned exposure to visitors.

Avoid Confrontations

Except during training sessions, avoid exposing the dog to situations and people that may trigger the aggressive behavior. Bear in mind that the territorially aggressive dog is reacting because they want the intruder to depart. If a dog is allowed to threaten, and the subject then retreats, the dog is rewarded for showing aggression. This can cause the unwanted behavior to increase in frequency and intensity.


Counterconditioning interrupts unwanted behavior by training the dog to respond to a command or activity that is incompatible with continued performance of the aggressive behavior. This technique is most effective when owners can identify and predict the situations that trigger the dog’s territorial response. If the dog can be distracted by food rewards or games, counterconditioning on its own may circumvent the brunt of the problems.

For dogs that do not readily respond to food or play, it is helpful to train them to relax on command by responding to verbal and visual cues from their owner. Under non-stressful conditions, owners should teach their dog to sit and watch them in order to receive praise or a food treat. First say, “watch me,” and move a finger toward your face. If the dog responds by paying attention in a relaxed and focused manner, reward them with a small food treat or praise them lavishly. Perform this relaxation exercise daily for 5 days. Each day, increase the amount of time that the dog must pay attention, in a relaxed pose, before they receive a reward. By the end of the fifth day, the dog should be able to remain focused for 25-30 seconds no matter what the distraction.

At this stage, whenever owners sense that their dog is about to engage in the unwanted behavior, they can use this counterconditioning technique to interrupt the behavior before it escalates. It is important to practice this exercise on a periodic basis to ensure its effectiveness when it is needed.

Indoor Counterconditioning

For indoor sessions, owners can also train the dog to perform a 20-minute “down-stay” on a specific bed or mat that is used only for training. Once the dog has learned the basic obedience commands, they can be trained to perform long down-stays while the owner moves progressively farther away. First, train a “down-stay” on a mat or dog bed. Initially, reward the dog every 10 seconds if they remain still, then every 20 seconds, 30 seconds, and so on.

Once the dog understands the concept of the long “down-stay,” the owner can switch to supplying rewards intermittently. Every time the dog breaks the stay, a verbal correction should be given to indicate that there will be no reward, and the dog is escorted back to the mat. The dog will quickly learn that if they break the stay, they will be put back on the mat, but if they hold the “down-stay,” they will be rewarded. Once a dog performs a reliable “down-stay” when their owner is in the room, the owner should ask for this behavior as they move progressively farther from the dog. Next, the “down-stay” should be utilized while the owner is in the room, but otherwise occupied. Then the dog should be required to remain in position as the owner exits the room, but remains nearby. The distance and time the owner is away from the dog should be increased until they can remain in a down-stay for 20-30 minutes in the owner’s absence.

Counterconditioning to People and Uncomfortable Situations

The next step is to countercondition the dog to people and situations that trigger aggression. All exercises should be performed on lead, preferably with a head halter, and basket muzzle, if necessary.

The key point to remember is not to suddenly expose the dog to the full intensity of the stimulus but to very gradually “up the ante.” At no point should the dog be allowed to become aggressive during training. If they appear agitated, the training has proceeded too quickly and the owner must return to an earlier stage. For desensitization, the owner should start by exposing the dog to people that they are least likely to be aggressive towards and train the dog in a location where they are most comfortable.

Steps for Exposing Your Dog to Strangers

  • Ask the dog to “sit and watch me” or remain in a “down-stay.”
  • Introduce a mildly anxiety-inducing person at a distance. For example, it may be possible to cue the dog to lie down in a relaxed posture, or sit and watch their owner, while a stranger walks by the end of the drive, rewarding the dog with a food treat for remaining relaxed, calm, and in position.
  • Next, the stranger may stop at the end of the driveway and momentarily walk onto the dog’s property before leaving again.
  • After doing this several times, eventually the stranger should be able to stand a few feet from the dog while it remains calm and under control. At this point, the stranger should be asked to toss one of the dog’s favorite food treats toward them.
  • Next, the dog can be trained to rest on a training mat or sit while focused on the owner when a visitor approaches the door.
  • Once the dog calmly accepts the stranger’s approach, the visitor can knock, and eventually enter the home as long as the dog remains quiet and relaxed. Treats should be supplied if the dog remains calm. If the dog prefers, visitors can present the dog with a tennis ball or other preferred toy.
  • If these exercises are performed frequently enough, and with an assortment of strangers, starting with the least threatening and working up to the most threatening, the dog will learn that their presence is associated with positive experiences. This concept will replace the prior aversion and need to repel borders. If the dog is resistant to remaining still, an alternative strategy is to have the person stand still and walk the dog around the person in progressively decreasing circles.

Tips for Training Assistants

During the early stages of training, assistants should be advised not to make direct eye contact with the dog and not to approach the dog head on. Rather, they should be asked to avert their gaze and advance slowly in a circuitous path (as this is less threatening to most dogs). No stranger should reach toward the dog at this stage.

If the dog cannot maintain the required posture and affect, and remains tense, barking and lunging at the stranger, the owner needs to return to an earlier phase of training. Ideally, during the training process, no one should come close enough to the dog to trigger an aggressive response. If someone approaches too closely, and the dog becomes aggressive, the assistant should stand still until the owner can get the dog’s attention, preferably using an obedience command, like “cut it out,” and rewarding the dog for their compliance. The owner can then ask the person to quietly retreat to a distance at which the dog was previously comfortable and resume training (as long as the dog is not too aroused).

For dogs that are aggressive when people enter the house, it is best to isolate the dog at first and then, once everyone is seated, the dog can be brought into the room on a lead and head halter, if they remain relaxed. At this early stage of the treatment program, if the owner has the dog in the room with guests, the dog should be removed before the guests prepare to leave.

Once the dog remains relaxed when people are quietly sitting in the home, they can be taught to accept them moving about. Owners can start by having the guests slowly stand up and then sit down. If the dog does not respond aggressively, visitors can be asked to try taking a few steps before returning to their seats. The amount of movement the dog will tolerate, while remaining relaxed, should be increased incrementally. Bear in mind that dogs with fear-related aggressive behavior have a tendency to snap at people when they move away, for example, when they are preparing to leave. If the dog is sitting or lying down and appears relaxed in the visitor’s presence, the visitor could slide a small food treat toward the dog, if this will not startle them. The goal is to teach the dog to associate a visitor’s presence with pleasant experiences.

Interacting with Visitors

Once the territorial dog is reliably relaxed with visitors in the home, they can be permitted to interact with them. The dog should initiate all interactions with visitors in the home. If the dog chooses to approach a guest, have the person quietly offer their hand for the dog to sniff and they may offer a treat if the dog is not too “grabby.” If the dog indicates that they would like to be petted, the guest may do so briefly, but again they should avoid reaching up and over the dog’s head and they should avoid prolonged eye contact.

These exercises should be repeated with a variety of different people. Assistants and visitors should be asked to engage in a variety of different activities so the dog learns that they are not threatening.

Avoid Punishment and Reassurance

Whenever the dog is behaving in an aggressive manner, they should be ignored or controlled. Neither punishment nor reassurance are appropriate actions. Punishment has the potential to increase the dog’s anxiety and worsen the situation. Reassurance will affirm the dog’s fear.

Territorial aggression, when confined to barking at the sound of approaching strangers can be a bane or a blessing, depending on the circumstances and the owner’s control of the situation. If it is a bane, the owner can do something about it using the approaches described above, and can frequently make inroads into containing the problem. Territorial aggression that has advanced to the point of lunging, snarling, and biting is more difficult to treat and positive results, though eminently possible, are not guaranteed.

For difficult cases, it may be helpful to treat territorially aggressive dogs with anti-anxiety, anti-aggression medication. Clomipramine (Clomicalm®), fluoxetine (Prozac®), and buspirone (BuSpar®) are all reasonable treatment options. The efficacy of such treatments will vary from case to case, but price, side effects, and other logistical concerns will determine the order in which these treatments are used. Most medications take several weeks to achieve their peak effects. Typically, these treatments are applied for at least four to six months, and possibly for as long as a year or two. Needless to say, appropriate behavior modification therapy should be conducted simultaneously to take advantage of this therapeutic window.

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