Dogs have wide vocabularies; they use a number of sounds to communicate their mood and intent to other animals. Growling is one of these, and it's commonly associated with aggression -- but there’s more to a growl than meets the ear. If your dog is growling when he meets other dogs, it’s essential not to assume he is being aggressive. By observing his body language, the context of the growl and the reaction of the other dog, you can accurately determine the meaning of the growl. This way, you can judge whether your intervention is required at all.
Growling is typically either a sign of aggression or a sign of play. A low-pitched, long growl accompanied by a fixed stare or sideways glance, curled lip and still, outward pointing tail is a sign of aggression. A slightly higher-pitched, shorter and louder growl accompanied by a bowing posture, wagging tail and erratic or energetic movement signals play. A play growl is your dog’s way of initiating fun.
Observing the context of a growl gives you a lot of information about its meaning. If your dog is growling at a regular playmate during a session of tug-of-war or chase, it’s safe to assume it is a benevolent vocalization of enjoyment and excitement. If the growl occurs because a strange dog has approached yours and isn’t showing great manners, assume your dog is growling because he feels threatened.
An aggressive growl is typically a last warning. Dogs do a lot of communicating before they get to the growl. They use posture, tail position and eye contact -- or lack thereof -- to communicate their mood before using their growl. They even use their ears and lips to show how they feel. So if your dog is growling aggressively at another dog, it’s because the other dog ignored or didn’t spot the early communication. This may be because he isn’t well socialized or because he wants to assert his dominance over your dog. Play growls, on the other hand, are typically spontaneous and come as a result of excitement and contentment.
Fear and dominance cause aggressive growling. Your dog may feel trapped or threatened; the other dog may be doing something your dog doesn’t like, such as sniffing or attempting to mount him; or your dog may simply be a bit of a bully himself and is trying to show the other dog who's the boss.
Understanding the meaning of the growl, by judging the context and monitoring the body language, is the first step to addressing the problem. Once you’re satisfied you know what the growl means, you can act. If your dog regularly growls when meeting new dogs, put him on a leash when you're in public from now on. If he becomes fearful and starts to growl, guide him away and give him a time out. If he is attempting to assert himself, gently tug the leash to get his attention, then correct him.