Your dog communicates with you and other dogs in a variety of ways — including growling. Depending on the context, a growl can be anything from a sign of enthusiastic play to a warning of an impending attack. It is important to understand why your dog growls and when you should be concerned about this behavior.

A growl doesn’t always signal an unfriendly dog. Here are some common reasons your dog might growl and some situations where you may need to seek outside help.

Growling in Play

Growling in Play

Dogs often growl during friendly play with other canines. This type of growling is typically higher pitched and shorter in length than other growls. To ensure that play is friendly, watch for the proper play signals and keep arousal levels low by taking frequent breaks.

Your dog may also growl when he plays with you. Pay attention to your dog’s body language during play — sometimes growling can indicate discomfort. Avoid rough play with hands and physical wrestling. If you are unsure about the distinction between acceptable play interactions and aggression, seek help from a professional.
Growling as a Warning

Growling as a Warning

A dog who is afraid of something may growl to fend off potential harm; the message he's sending is that he will defend himself if necessary. Some dogs may growl at any unfamiliar person, while others may respond only to specific types of people, like men with beards, or to sights they are uncomfortable with, such as a horse. If your dog growls only at specific people or things, remedial socialization help is needed.

Or your dog may growl at another dog as a way to tell him to back off before a confrontation occurs. Many times, the other dog will heed the growl and give your dog the space he desires. There are dogs, however, who will not back down when they are growled at; in this situation, a fight may ensue. 

If your dog’s warnings to back off go unheeded, his growling may increase into other aggressive behaviors, making it difficult for him to be around other canines. Some dogs do best with only select doggy playmates, while others should be limited to socializing only with humans.
Growling for Medical Reasons

Growling for Medical Reasons

If your dog suddenly starts to growl when he is approached or touched, it may be a sign that he is in pain. Dogs with arthritis, abscessed teeth or other forms of illness or injury may experience increased pain when they are moved or touched and may growl to avoid it. A pet in pain is also more likely to bite than a healthy pet.

Pregnant or lactating dogs, or dogs in false pregnancy, are more likely to be protective and defensive with people and other animals, and are also more likely to growl at approaching humans. If you think your dog is growling for medical reasons, talk to your veterinarian.
Growling Out of Frustration

Growling Out of Frustration

Your otherwise-friendly dog may growl as an expression of barrier frustration. A dog may growl or bark when he is on leash or behind a fence, even if he is comfortable with other dogs when he is off leash. Dogs who growl in these situations need to be trained to relax when on a leash or behind a fence, as territorial or frustration-based behavior can escalate over time. Your dog should never be chained up outside, as this can lead to extreme territorial and protective behavior, which puts the dog, other animals and people in danger.
When to Seek Outside Help

When to Seek Outside Help

Growling is a way of communicating — for instance, his way of saying, "Give me space," "Stop it," or "Back off." But certain situations — growling when approached or handled, and growling as part of resource guarding — require professional help. A dog who is engaging in resource guarding may be protecting food, toys or people, or his favorite places, like a sleeping space. Even with the best management plan in place, a guarding dog may escalate his aggression, which is why this behavior calls for professional intervention.

Your dog may also growl when he is handled, either because he is uncomfortable or afraid. He may growl when his collar is grabbed, his toenails are trimmed, his ears are touched or his mouth is opened. He may also be uncomfortable with direct eye contact, a person leaning over him, hugs or other forward greetings. Again, this behavior can escalate to something much more dangerous.

Talk with your veterinarian about these behaviors as soon as possible; have your pet’s health evaluated and, if necessary, ask for a referral to a behaviorist or trainer who can help you teach your dog strategies for coping with these situations.
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