I'm not a particularly imaginative person when it comes to blog posts. I generally draw from my work as a dog trainer, which comes with its fair share of dispelling long-standing myths about dog behaviour, so this one is seriously overdue.
Growling. There are a couple of different kinds of growl, pretty easily distinguishable by the context in which they are displayed, but I want to focus on growling meant to create distance between the growling dog and the recipient of this vocalization. This is the growl that, unheeded, can lead to a bite, the one that sends countless dogs to shelters, and more unfortunately still, into the hands of an inexperienced dog trainer, who sees growling as a hierarchical transgression to be dealt with with an iron fist.
This isn't a post about behaviour change programs for aggression, that's a complicated topic, and not appropriate for a quick post. The only sure, safe response to a growl is to stop doing whatever you did to cause the growl, and move away if space is the issue. If you pet your dog and she growls, stop petting her. This isn't a training technique, it's management, nay, self-preservation.*
This post is about the visceral reaction we have to our dogs growling at us. The most common reaction I hear is offense, especially in owner-directed aggression. Don't get me wrong, I fully understand the logic behind it: you give your Fido all the food, love, toys and care he could want, sometimes even too much, and he repays you by growling if you try to take away his toy or sit next to him on the couch. On top of that, we're raised to think of dogs as subordinates, who are supposed to just know and accept their role as a doormat. It's all too easy to take exception to a growl from that standpoint.
You know what most (educated) dog trainers think when a dog growls at them? Thanks. Yup, that's right: thanks. Thanks for growling, and not biting me instead. A dog who growls is telling you, "I don't want to bite you, but I need you to stop/let go of me/move"
Growling shouldn't be seen as an affront, nor to be taken personally. It's a dog's way of expressing discomfort. Not all dogs growl, some will simply move away, some will not hesitate to lunge, snap or bite, while others will show less-evident signs of discomfort, which usually go unnoticed by most humans.
*I'm not suggesting that you walk on eggshells around your dog, but the moment that your dog growls at you is not when you should be playing 'quien es mas macho.' Aggression is certainly something you should seek help for, but starting when your dog is growling at you is like deciding to learn to drive the moment you get into an accident. You can certainly handle your next commute better with the right knowledge and tools, but right now what you need is a tow-truck, not a driving instructor. Get out of the situation you're in, then contact a professional.
If you feel you aren't qualified to handle your dog's behaviour, whether it's aggression-based or not, please seek the help of a professional. I can't tell you the times I've gotten a distressed call from a family who watched a dog training tutorial video, and ended up leaving out an important step or detail, or possibly moving forward too quickly, and wound up with a bite. As a side-note, this is why I am hesitant to dispense advice outside of a consultation: very rarely is five-minute instruction adequate to solve a problem, especially if I haven't even seen the dog or behaviour in question.
Good luck, and happy training!