Growling in Dogs

When, if ever, is growling acceptable? When should it be cause for concern?

A growl is a guttural vocalization most commonly emitted by an animal during agonistic interactions—situations of threat or defense.^1,2 Dogs growl at humans and other animals in various circumstances; the following focuses on growling directed toward humans. However, the purpose of growling and principles for addressing it are the same regardless of the intended target.

Why Do Dogs Growl?

Growling is a true communication signal, the purpose of which is to influence the behavior of the receiver. Growling in agonistic situations is a distance-increasing signal in which the goal is to get the receiver to stop its advance or interaction and withdraw.

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Growling can also occur in the context of play. In this case, play metasignals occur to let the receiver know that the growling is nonthreatening. (Metasignals, such as a play bow, are essentially modifiers—gestures or actions a dog takes that put the subsequent behaviors in proper context so the receiver knows how to respond.) Dogs may also growl as a means of seeking attention. This is a learned behavior that often originates from play. Similar to play, other body signals associated with threat or defense will be absent during attention-seeking growling.

Dogs also may growl when approached by unfamiliar people or dogs, during handling or maintenance procedures (eg, nail trims, vaccinations), when the dog is verbally or physically reprimanded, or when someone tries to take away a high-value possession.

Of note, growling is not a diagnosis; it is a clinical sign. Like any other clinical sign, growling signals an underlying problem that needs to be addressed (see When Growling Is Not Normal).

When Is Growling Good?

Growling is one stage of threat intensity. A dog’s early warning may include signs of fear or avoidance, such as turning the head away, licking the lips, pinching the ears back, cowering, and/or freezing. As the intensity of the threat—and therefore the dog’s response—escalates, this may intensify to growling, snarling, snapping, and biting.

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In a perfect world, these behaviors occur on a distinct continuum—that is, a protracted warning phase before escalating to biting. In reality, however, threat behaviors may occur in a less predictable sequence, simultaneously, or with some behaviors entirely absent. Dogs may show extremely brief warning sequences giving the impression that they bite without warning. This may occur in part because warning signals such as growling have been modified through learning (eg, punishment, reinforcement).

There is some suggestion that suppression of growling can occur without accompanying suppression of fear or biting. In other words, a dog can be conditioned to skip growling as a warning and go directly to biting. This is most likely to occur in situations where dogs are punished when they growl but someone continues to threaten or antagonize the dog. For example, if a dog is punished for growling at an approaching visitor, the owner may be successful in eliminating the dog’s growl. The dog may sit quietly without growling while the visitor approaches, but the dog is still fearful. (The dog is likely still displaying other subtle or clear signs of discomfort or anxiety, but these are frequently missed by owners and visitors.) If the visitor reaches toward the dog, it may still bite because suppression of the growling did not address the dog’s underlying fear. Absence of growling and lack of recognition among owners of other signs of fear can create a dangerous situation for both humans and dogs.

Although people may not like the fact that a dog feels the need to growl, the behavior does serve as a warning of its discomfort before the dog resorts to the more dangerous behavior of biting.

How Do We Handle or Treat Growling?

As with any other clinical sign, treating the underlying cause of growling is important. When a dog scratches, we discover, then treat, the underlying cause of the pruritus. Similarly, we do not focus on treating growling directly. When a dog growls, it is telling us there is a problem that, if not addressed, may escalate in the future to something more intense (eg, biting).

The first step is to identify the immediate antecedent for the growling—the specific action that occurs immediately before growling begins. The second step is to determine the function growling serves for the dog—the when, where, and toward whom (see Important History Questions).

The most immediate response that occurs after the growl likely has the most impact on reinforcing growling. For example, consider a dog resting on the couch: the owner approaches and tells the dog to get off. Because the owner has never systematically taught the dog the off command, the dog is unclear about what it should do and remains on the couch. Now the owner points at the dog, leans forward, and tells the dog more firmly to get off. The dog turns its head away slightly but remains on the couch. The owner then reaches to pull on the dog’s collar and the dog growls. The owner pulls his or her hand back and walks away. The dog now gets to remain on the couch, but the most immediate reinforcer for the dog was the owner removing his or her hand from the dog’s collar and withdrawing the threatening postures. Whereas the owner thinks the dog is growling to stay on the couch, the dog may actually be growling to get the owner to stop threatening it.

This distinction is important in helping owners formulate solutions because the final step is to devise a behavior modification program to treat the underlying problem. In this example, the approach for growling is to systematically teach the dog to get off the couch on cue using positive reinforcement, so the owner does not have to resort to threatening the dog and pulling on its collar.

Conclusion

Growling is a valuable warning sign that allows us to decipher a dog’s tolerance level for a certain situation or action without direct injury. Growling should be addressed by determining and treating the underlying reason for the animal’s behavior (eg, fear or anxiety), not by punishing or correcting the growling itself.

LORE I. HAUG, DVM, MS, DACVB, works in a private referral, behavior-only practice in Sugar Land, Texas. Dr. Haug, who is certified through the International Association of Animal Behavior Consultants, speaks routinely to veterinary groups and animal trainers across the country. Author of numerous articles and book chapters, Dr. Haug is co-author of Decoding Your Dog by the American College of Veterinary Behaviorists.