Growling and barking are very natural ways for dogs to verbally communicate with people, other dogs, and other animals. A dog's growl may not be a pleasant sound, but it's an important part of his behaviour pattern—and one you should understand.
When a good guard dog feels his territory is being threatened, he barks or growls. And since he does this at people or dogs that are passing by, he feels he did his job by protecting his home turf and the family in it that he loves.
What can you do to control it? A simple way to help control his growling in this situation is to block his view of the street or property line.
Working and sporting dogs often bark due to sheer boredom. These dogs were bred to run around and to work the great outdoors. So to make up for the lack of aerobic exercise, they choose to exercise their vocal chords by barking or growling.
What can you do to control it? You can help to alleviate his boredom by setting aside a couple of extra hours each day for some energetic and fun playtime.
If you obtained your dog from a shelter it is possible that he may have a history of neglect and abuse. Through no fault of their own, these dogs were never given the opportunity to develop proper social skills early on. Thus, they growl and bark a lot.
What can you do to control it? A great deal of patience is required in these cases. Dogs with a history of neglect or abuse take a bit longer to train, but with a little understanding and extra care in building trust, in time they can come around. It's important not to reinforce the behaviours you don't want your dog to repeat.
Growling is not uncommon with aging dogs. In many cases it's an early sign of senility. Put another way, he may be becoming a grumpy old dog. But there are things you can do about it.
What can you do to control it? Reward-training and disruption techniques can work well in some cases. It's important to be patient and consistent. Contrary to popular belief, you can teach an old dog new tricks.
In more extreme cases, his growling could be due to a genuine medical condition, such as joint pain exacerbated when "kindly" strangers touch him. For those types of conditions, drug therapies can help. If your senior dog has suddenly begun to growl often, take him to the veterinarian for an examination and to discuss your options.