Living with a constantly growling dog can be a frustrating situation. Since canines don't communicate in human language, asking what is wrong can't help. Process of elimination can be helpful in determining the cause of a dog's seemingly nonstop growling, however, whether it's coming from aggression or classic dominant behavior.
"I'm So Scared"
If you hear your dog growling all of the time, it may mean that something is frightening him -- say the frequent sight of the massive Saint Bernard he can see gazing at him from your neighbor's backyard. By growling at the sight of something intimidating, your dog may be in protective mode. He's apprehensive about a possible attack from something potentially much stronger and more powerful than him, and he's gearing up to defend himself.
"I'm a Tough Guy"
A dog may growl nonstop out of the aggravation of another canine simply being around. If your dog has a habit of growling at another dog you regularly pass on your morning walks, it may be because he feels self-assured -- and mighty -- while in the presence of this other pooch. He may be making an attempt to assert his strength -- and drive the other party far away.
"I"m the Leader"
A growling dog is often a sign of a dog with dominance issues. If your dog doesn't think of you as being "the leader of the pack," and instead views himself as the big guy in charge, he may respond to many of your actions by growling at you. If a dog growls at you every time you attempt to put a leash on him to take him outside, for example, he probably thinks of himself as being the boss, not you -- uh oh.
"Mine! Mine! Mine!"
If your dog growls every time he senses that someone else is about to encroach on his belongings or individual "turf," then his canine territorial streak may be out in full force. Whether your dog growls menacingly every time your Siamese cat gets just a little too close to his bowl of food or whether he does so every time a house guest goes near his bed, he is warning the "trespassers" to stay away from his possessions.
"I'm Just Having Fun"
Happy and excited dogs also, strangely enough, sometimes growl when they're in the midst of lighthearted play. From producing piercing barking sounds to running after others, jumping and growling, dogs often express their "joie de vivre" in diverse -- and sometimes misleading -- ways.
"I'm in Pain"
Constant growling can also point to a poor dog who is injured or otherwise in pain, perhaps due to illness. If you notice that your dog growls any time you approach him to pet or hold him, it may be due to the discomfort that physical contact brings. It is important to rule out this possibility by taking your doggie in for a veterinary appointment -- the sooner the better.