Dogs do what works. Change in dog behavior is simply your dog responding to his environment at that moment. What he does one day will not necessarily be what he does another day.

Let me start off by addressing the ideas behind pack theory.

Much of the information on understanding dog behavior originally stemmed from wolf behavior. Wild wolves rely on a complicated social structure which came to be known as a pack. While it appears logical to apply wolf pack behavior to our dogs it is misleading. Our domestic dogs are not wolves.

Your dog isn't a wolf. Wolves, coyotes, foxes, and domestic dogs occupy the same category: canid. Like apples and oranges are both fruits, they both have seeds, skin, and grow on trees, but they survive differently. Wolves and domestic dogs are both socially complex. Today it is understood that wolves do not follow a strict pack behavior protocol. It is also understood that domestication genetically changes the way an animal survives.

Domestication expresses itself in the way our dogs interact with other each other, humans, and their environment. Hypothetically, our domestic dogs cannot survive without us. Domestication changes other things too, from stomach enzymes to estrus cycles and litter sizes. For indepth reading on the domestication of dogs get Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution

Enough of domestication, you are here to understand change in dog behavior.

The cool thing about breaking free from pack theory is it allows us to move away from labels such as dominant and submissive. If you think about it, the word dominance is not a behavior. Sitting is a behavior. Barking is a behavior. Growling is a behavior. I call my dog Kyra sweet, but is sweet a behavior? No. Sweet was put together (constructed) out of several behaviors that I have observed from Kyra. And what I think is sweet you might think is shyness.

Understanding change in dog behavior first requires us to identify behaviors that are observable. Let's say your dog has started barking. Barking is an observable behavior. Now you can break that down into what happens immediately before and immediately after he barks. Does he bark immediately after you leave the house? Let's look closer. Does he start barking the moment he hears the door shut? Look closer. Does he bark when he hears the click of the door handle? The start of the car? Try to find the thing that starts the barking.

Looking closer at behavior. You have figured out what makes your dog start barking. Now when does he stop. When you walk in the door? When the squirrel is out of sight? When the other dog is out of sight? When you walk in the door? When you walk up the stairs?

Putting it all together. First, thoroughly desribe the behaviors that you are worried about in writing. Describe it as if the person listening has no idea what a dog looks like or acts like. (If someone said to you, that snake is shy you probably wonder exactly what behaviors make a snake shy - do they move away as you approach? do they roll over onto their back?) Next, write down what happens immediately before the behavior starts. Narrow it down as much as possible. Then, write down what happens to make the behavior stop. You head out the door on your walk. Food is delivered.

When does the behavior happen? An important part of understanding change in dog behavior is be able to describe when it happens. Does your dog always lunge at other dogs while walking on a leash or is it only certain dogs. Does your dog growl at other dogs or only some dogs? If he growls at some dogs where and when does he do it? Does he only growl at dogs in the dog park? Does he only growl at dogs when on leash? The more specific you are at describing the exact behavior and when it happens the better you can figure out how to change it.

Dogs do what works and that means that dogs are always learning and changing their behavior to negotiate their environment at that time. For example, if your dog growls at you when you grab his foot with a nail trimmer in your hand and you let go of his foot, growling worked. If you continue to hold his foot and he bites and you let go of his foot, biting worked. If he growls and you muzzle him and throw him to the ground he will change his tactics the next time. More than likely he will leave out the growling and go straight to the biting because what he learned previously was that growling resulted in being muzzled and thrown to the ground.

The dog changed his behavior based on the circumstance. Two things are wrong with applying stronger and stronger methods. One is that you never address the initial behavior which is to peacefully accept nail trimming. Second, there is no forseeable end to the violence. The harder you restrain, muzzle, shock, jerk, or yell, the more your dog is forced to defend and protect himself which brings both of you further away from the behavior that was wanted and that was to accept nail trimming.

Other factors that change behavior involve pain and illness. Something as insidious as back pain can change the entire demeanor of your dog. Irritated paws, itchy ears, painful stomach, tumors, and infection can all change dog behavior. If you dog has started sleeping in odd places, following you around excessively, growling when touched, or started going potty in the house it's time for a veterinary checkup. It' difficult to change dog behavior when their is an underlying illness.

Dogs have their own language. Some of that language is vocal, but most of it is physical. Wagging tails and snarling teeth offer about 10% of the body language your dog is communicating. Good dog trainers are gifted at reading dog language and have great timing. To learn to read all the body language of dogs get How To Speak Dog: Mastering the Art of Dog-Human Communication