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Why Dogs Growl

Growling isn't as simple as it seems, and sometimes it's entirely appropriate.

A few days ago, Italian dog trainer Debora Segna contacted me about a Facebook posting by veterinarian and philosopher Dr. Roberto Marchesini in which he wrote:

“If my dog would growl at me during an interaction, not a playful growl during a playing interaction, but a warning and threatening growl, I would question the relationship I have built. For me it wouldn't be a simple demand, but rather my failure. Obviously I am not talking about adopted adult dogs, with several problems you need to work on. In my life I have had countless dogs, and the ones I had since when they were puppies never growled at me. The ones I get from shelters sometimes did in the first times, but eventually gave up. I see a tendency to underestimate a behavior that is always a warning light of a dysfunctional relationship” (Translated by Fabrizio Giammatteo).

So, according to Dr. Marchesini, growling outside of play is unacceptable in interactions between a dog and their human companion. (See Note 1 for the original Italian post. This essay titled PERCHÉ I CANI RINGHIANO is available in Italian.)

Source: Alexei_tm/Shutterstock

Growling is a complex behavior/vocalization, and I don't see it as indicating a failed or dysfunctional relationship. Dogs are vocal animals, and most of us have heard a variety of canine sounds, from growls to barks, whines, and whimpers. But how good are we at determining the emotional state of a dog when she or he is growling? A new and very important study by Hungarian researchers T. Faragó, N. Takács, Á. Miklósi, and P. Pongrácz called "Dog growls express various contextual and affective content for human listeners" shows we're pretty good at assigning context and emotional state to different growls, and that women are better than men at doing so. For a discussion of this important study, see "Dogs Growl Honestly and Women Understand Better Than Men."

I can well understand why a dog would growl or otherwise tell a human they don't like something that they are doing or are otherwise uncomfortable. Simply put, they're annoyed. A growl does not always mean that a dog will attack a human or necessarily do anything more than vocalize what they're feeling. It is a way for them to say something like: "Back off, this is my ball or my food, and I don't want to share it with you," or "I'm sleeping, and I would appreciate it if you wouldn't disturb me." In fact, we should welcome this sort of response, so that we know that there are clear boundaries about what the dog would like you to do.

When a dog is vocalizing, we also need to pay careful attention to their body language — where their tail and ears are, as well as their posture or gait, for example, because dogs often communicate using what ethologists call "composite signals" that contain information from different sensory modalities. Composite signals also may contain more information than signals in a single sensory modality. (See "Do Dogs Recognize 'Dog' and What They're Feeling From Afar?" and Unleashing Your Dog: A Field Guide to Giving Your Canine Companion the Best Life Possible.)

I don't agree when Dr. Marchesini writes that growling is "always a warning light of a dysfunctional relationship” (my emphasis). In many ways, growling is indicative of an ongoing relationship in which a dog is telling a human what they want and need, and a mutual and respectful relationship requires reciprocal understanding and respect. This is not to say that growling is necessarily welcomed, but rather to say that growling can be a nuanced signal and communicate subtle messages that are all part of a healthy relationship.

When growling is part of a composite signal, it can be more difficult to assess what a dog is trying to communicate. For example, when growling takes place during playful tug-of-war and a dog is vocalizing and expressing other behavior patterns, it's not necessarily because two dogs or a dog and a human are competing with one another. (See "What's Happening When Dogs Play Tug-of-War? Dog Park Chatter.") They can just be having fun. Concerning tug-of-war, in her book called Play with Your Dog, dog trainer Pat Miller wrote, “Tug to your hearts’ content,” and don't worry if your dog growls. It's all “part of the game,” and if the dog's other behaviors are appropriate, “let him growl his heart out!” I agree, and I also feel the same when a person engages in rough-and-tumble play with a dog, and the human is sure that the dog enjoys it, and that it remains a playful interaction. Getting down and dirty with a dog is an incredibly special time filled with frivolity and unbounded joy, as long as it's on the dog's terms. (See "Get Down and Dirty With Your Dog: Bow, Hug, and Tug.")

It's essential for people to learn to speak "dog"

It's essential for people to become fluent in dog — dog literate — so that they can understand what a dog is communicating when they perform a specific behavior patterns or utter a particular sound. As I emphasize in Canine Confidential: Why Dogs Do What They Do (to be published in Italian in early 2019 with the title Nella mente e nel cuore dei cani: Vita emotiva e comportamento del vostro migliore amico), if humans are good at understanding what dogs are saying and feeling when they're growling, it could help us better understand what they're doing or likely to do in a given situation. As University of Sussex (UK) animal communication expert Holly Root-Gutteridge notes in her summary of the above study by the Hungarian researchers, "Learning about these differences may help in reducing dog aggression towards humans, as well as improving dogs’ behavior, as we understand better when a threat is real versus playful.”

When a dog growls, it's a good time to reassess the dog <--> human relationship

"My Labrador growls when she runs out of words. She is not mean, or threatening." (email to me in response to this essay)

"My Barney always growled playing tug-of-war, and also when he's lying down sleeping and I give him a kiss, he gives me a light growl to say, leave me alone and let me sleep!" (email to me in response to this essay)

When a dog growls, it's a good time to reassess the relationship a person has with their dog(s) and to come to an understanding of why the dog growls in certain situations. It's surely not the time to punish a dog for "something they should never do" or for "something their human doesn't like," because often it's the only way a dog can set boundaries. I'm not saying that Dr. Marchesini suggests that dogs should be punished for growling outside of play (or when they growl during play, something I've witnessed), but rather I'm suggesting that when a dog growls outside of play, there's likely a very good reason they're doing this, and it's time for a human to figure out why and to come up with a solution that reduces growling to a bare minimum and hopefully gets rid of it altogether. There's also a good lesson here for a dog to inform a human about what they like and dislike, and for the human to let other people also know this.

One of the dogs I rescued years ago growled when another dog or a person, including myself, came near him when he was eating or playing with food. I was able to teach him not to growl on most occasions, especially when I was the human intruding on "his food," and his growls became less intense and, on occasion, almost inaudible. I also came to realize that — most likely because of how he was treated (or mistreated) when he was young and on his own and had to find and defend food before he went to the local humane society, and I brought him home — growling was his way of saying, "Please leave me alone," or "This is my food, and I need it." He never did anything more than growl, and I would tell other people to leave him alone when he was around food. That worked very well — there never was any aggression, and all he did was growl a few times and then stop — and other dogs also learned very rapidly to leave him alone when he was around his food. We did not have a failed relationship, but rather a very deep and enduring friendship for many years. Another dog I rescued didn't like people to touch his front feet, so, once again, I honored that and told other people not to try to touch his front feet. There never was a problem, even if he growled to show how he felt about it. I've heard numerous similar stories from many people about the situations in which their otherwise friendly dog would occasionally growl, and there was no problem at all.

Decoding what dogs are saying and feeling — accurately reading their moods — is necessary if we're to live harmoniously together. It's essential so that dog-dog and dog-human encounters will be as amiable as they can be. It is also crucial that we view each and every dog as the individual they are; no two dogs are the same, and there is no being called "the dog." (See "Let's Give Dogs a Break by Distinguishing Myths From Facts" and links therein.) Dogs, even young siblings, show incredible individual variation, and explanations of behavior patterns that might work for one, two, or even 10 dogs might not work for many others. One of the most exciting aspects of studying dogs centers on their marked differences in behavior, personalities, and how they adjust to living in a human-dominated world. And it's their individual variability and differences in the varying situations in which they're studied that's often responsible for differences in the results from experiments that focus on similar questions.

I very much appreciate what Dr. Marchesini wrote, because it is a good catalyst for beginning much needed discussions of growling, other types of dog behavior, and dog-human interactions. However, once again, it's important to stress that growling is not always a threat, and we need to study in detail the context in which it's performed, what else the dog is doing — for example, is growling part of a composite signal — and the individuals who are involved.

The more we understand dog behavior, the better it will be for the dogs themselves, other dogs, and humans — a win-win for all. All we have to do is pay careful attention to what dogs are telling us. It's really a lot of fun to become dog literate and to get to know the amazing beings with whom we share our homes and our hearts. I look forward to writing about the latest research and ideas about dog behavior and dog-human interactions in future essays.

Note 1: Dr. Roberto Marchesini's original Facebook post:

“Se il mio cane mi ringhiasse in una qualche interazione con lui, che non fosse il ringhio scherzoso del gioco ma un ringhio di avvertimento minaccioso, mi porrei delle domande sul rapporto che ho costruito. Non lo vedrei come una semplice rivendicazione ma come un mio fallimento. Ovvio, non parlo di cani adottati già adulti e con mille problemi, dove occorre lavorare. Ma nella mia vita ho avuto tantissimi cani e quelli tirati su fin da cuccioli non mi hanno mai ringhiato. Quelli presi dal canile magari i primi tempi lo hanno fatto, ma poi hanno smesso. Vedo che c’è in giro la tendenza a sottovalutare un comportamento che viceversa è sempre una spia di un disagio di relazione” (Translated by Fabrizio Giammatteo).