Editor's note: Victoria Stilwell hosts "It's Me or the Dog" on Animal Planet and is the founder of Victoria Stilwell Positively Dog Training, both of which advocate positive reinforcement during training.
(CNN) -- The shelter dog is often perceived as unpredictable and inferior to one that is bought from a pricey breeder or a pet store. The thought of giving a home to a dog with an unknown history also puts many people off. But while some dogs are relinquished to shelters because of problem behavior, most are surrendered because of a change in the family situation.
Shelters can be overwhelming places to visit, so give yourself time when going through the adoption process and make decisions with your head as well as your heart.
Because stress levels can be high in such an environment, dogs tend to exhibit behavior that does not reflect their true personality. Don't be put off by a dog that stays at the back of the kennel too tired or nervous to greet you, or by the dog that leaps at the kennel door like a lunatic as you walk past. Remember these dogs may behave very differently once out of confinement.
Look for a dog that recovers well when taken outside the kennel. One that runs and is excited to interact with you, your family and other people. If you already own a dog, bring it along and allow the two dogs to greet in an outdoor neutral area to see if they will be compatible. Look for soft, wiggly body language, warm eyes and a desire to play.
If the shelter dog that you like seems removed and not interested in interacting with you, retreats or stiffens if you try to touch him, looks at you with hard eyes or is tense around your existing dog -- do not adopt that dog.
Dogs that are relinquished to shelters because of behavior problems can be difficult to re-home. Don't be afraid to ask the shelter staff about the dog's medical and behavioral history before it came to the shelter -- if known -- and behavior while it has been in their care. Try to get more than one person's opinion about the dog.
Adopters can easily be swayed by a well-meaning employee or volunteer who is desperate to find their favorite dog a new home -- even if the match is not a good one. If the dog you like has known behavior difficulties, ask the staff if they have been working with the dog on that issue and how the dog has responded so far.
Even if there are no obvious behavior problems, here are some other important questions to ask:
• Has the dog been tested around food or toys to see if he is protective of his resources?
• Does the dog stiffen, growl or try to bite them if they take a toy or his food bowl away from him?
• Has the dog greeted other dogs, and if so, what was the outcome?
• How is he with strangers and is there any different reaction to men or women?
• How does the dog act around children and has he been exposed to any cats?
• Does he like to play?
• Has shelter staff taught the dog to respond to verbal cues such as sit and stay?
A good shelter with knowledgeable staff will be happy to answer these questions.
Rambunctious behavior such as leash pulling, jumping up or barking can easily be worked with and dogs that have house training issues can be taught how to toilet correctly.
But anxiety-based behaviors such as distress upon separation or nervousness or aggression can be complex and take time to modify. It takes a committed owner with plenty of patience to help a dog through these problems and it might require the support of a qualified trainer.
The dog training profession is still unregulated and there are many people who call themselves trainers even though they have little knowledge of how to work successfully with problem behaviors and may sometimes do more harm than good.
Trainers who use outdated methods that can include dominating dogs into submission or teaching dogs to behave through force and fear should be avoided at all costs, as these techniques not only make your dog more insecure but also can damage the relationship between you and your pet.
There are many great positive reinforcement trainers who will teach your dog to live successfully in a domestic situation using humane methods only, no matter what problem behaviors your dog might have. You can find a list of positive reinforcement trainers in your area at http://positively.com/dog-training/find-a-trainer/.
If you don't have the time to work with a dog that has an anxiety-based issue, then it is best that you adopt a dog that will more easily fit into your lifestyle.
Dogs that have a history of aggressive behavior can be a physical, legal and financial liability to your family and the general public. A shelter can be held liable if they adopt out a dog that has previously bitten -- whatever the reason. Do not adopt a dog with a known bite history.
Bringing a dog home is an exciting time, but in the midst of everything, don't forget that a period of transition is needed. Some dogs adjust to their new home very quickly, while others might take longer to settle. So remember that while you're coping with the changes the new dog fetched into your life, your dog will be doing the same.
With approximately 4 million dogs and cats being euthanized in U.S. shelters every year, the need for families to adopt rather than buy is even greater. Adopting a shelter dog is a rewarding experience, not just because you give that dog a second chance, but because adopting makes space for another life to be saved.