Preventing Separation Anxiety
In worst-case scenarios dogs can get so worked up when alone that they can bark for hours, injure themselves by scratching or biting at doors or crates and even jump out of windows to avoid being left alone.
Dogs are social animals that like being around other dogs or people. They can become anxious if left alone for any length of time if they are not used to it. You need to get your dog used to being alone. Dogs can, unfortunately, quickly get separation anxiety if they associate being left alone with a traumatic event. If they are terrified of thunder and there is a thunderstorm while they are alone, they might associate being alone with thunderstorms.
They can also get separation anxiety if they are used to being with a member of the family constantly and then the person's schedule changes or they go away to college.
Signs of Separation Anxiety
- Pre-departure anxiety. Your dog notices the pattern of your routine and shows anxiety at a certain point in the process.
- Barking when alone. Dogs can bark for hours on end when left alone if anxious.
- Not eating food that they normally love when left alone.
- Scratching or biting at exit point or the crate, sometimes until damage to paws or teeth occur
- Greeting anxiety. When you come home they get very worked up and have trouble calming down.
- Accidents when gone. Usually within 30 minutes of being left alone, dogs with separation anxiety will have an accident, even if they are usually housetrained.
Strategies for Prevention
- Don't be with your dog 24 hours a day. They need to be left alone. Put them in their crate or other dog-proof area and leave the room. Make sure to do these exercises when you are in the house at first so the crate doesn't always relate to you leaving for long periods of time. DO NOT come back if they are barking or whining or that will teach them to be a persistent barker. If this is already a problem, ask questions. Start slow and build up the time until they can be left alone regularly for a few hours while you are in the home. This will make it easier to have friends over and manage their behavior without them barking the whole time.
- Don't make a big deal about departures or greetings. Ignore your dog right before you leave and right when you get home. You don't want the departure or greeting to be the cue for your dog to get stressed because he is going to be left alone for long periods of time.
- If you are ever going to kennel or have friends watch your dog, practice when they are young to get them used to it.
Preventing Resource Guarding
Dogs can exhibit object guarding, location guarding, food guarding, miscellaneous guarding or owner guarding. They usually show signs of more than one form. Dogs that show resource guarding quite often present signs of body sensitivity as well. Most dogs will show resource guarding around family members more than strangers, but that is who is most often near the dog.
Adaptive Significance
Dogs natural guard their resources in the wild. Once prey is taken down, each dog takes his or her piece of the animal. If they are weak, the stronger dogs take their food away. Dogs learn to guard their resources to stay alive. When we take them into our homes, we ask them to allow us to take away any food from them at any time, whether they know the person or not. This is an unfair expectation unless they have been taught to be comfortable when people take things from them.
Warning Signs
Dogs emit warning signs to communicate to others their intent. In some situations, dogs do not follow the normal pattern and quickly move up the chain and may skip or show only slight signs of each stage. You must be extremely aware of your dog's signals and pay attention to the stimuli causing the reaction. If you ever see new stimuli causing a reaction, your dog must be systematically desensitized to this new stimuli starting at the easiest exercise and working up the chain.
The normal signals include freezing or "glassy eye", increased speed of eating or chewing, growling, snarling, snapping and biting. Dogs do not try and bite and miss. If dogs intend to bite, they will bite. Some dogs naturally do not exhibit warning signs, others cover-up the signs if there is a history of being reprimanded for growling or barking. The fear is still there, but they will not show the signs for fear of punishment.
Warning signs are a good thing for dog's to exhibit because the signs, if heeded, stop the person from pushing the dog into biting.
Strategies for Prevention
Assuming there is no guarding at this time, play with your dog's food and then drop an extra yummy treat in his bowl, walk by his food bowl and drop something yummy into it while he is eating, touch him and pet him and give him something yummy while he is eating, give him chew toys and hold on to one end so he sees hands in the picture and gets used to them.
The pattern is that someone approaches him while he is in "possession" of something and it is a good experience for him. 

Keep in mind that dogs can be fine with their immediate family and then guard unexpectedly when guests come over. When your dog is young, have a variety of people -- including kids, (safety is always a top priority when dealing with kids, so be careful) do the prevention exercises when he is a puppy and periodically throughout his life to maintain it.
Preventing Destruction
To prevent dogs from learning bad habits, hurting himself or herself or the house it is important to manage their behavior. Even a dog that hasn't destroyed anything yet, has the potential to learn that the couch tastes yummy. With that said, with a puppy, it is recommended to either watch them or manage their behavior 24 hours a day.
Management options include:
- Crates
- Baby gates
- Exercise pens
- Attaching leash to your belt
- Tethering puppy to a hook in the wall with a comfortable length of leash (assuming your puppy does not chew on leash or anything in area)
It is important to not get lax in management. Take every opportunity to teach LEAVE IT, DROP IT, COME, etc. when there are possibilities of destruction, but also do not feel bad about putting your puppy in the crate when you don't have time to monitor behavior. It is important that puppies learn to be alone.