More than 57 million American households include at least one dog or cat. But unlike other varieties of pets, dogs and cats are the only companion animals that vastly outnumber the homes available to care for them. Their survival is threatened simply by the act of reproducing themselves, resulting in a staggering surplus of orphan pets. Every year, an estimated 5 million dogs and cats remain in shelters or are destroyed for a want of sufficient homes. In her book, The Pet Surplus: What Every Dog and Cat Owner Can Do to Help Reduce It, Susan M. Seidman outlines the many large and small ways thoughtful pet owners can make a difference and reduce this frightening shadow population of surplus pets.

I’ll be candid with you up front. In general, I’d like to discourage you and other pet seekers from acquiring an animal that was bred expressly to be sold. Most particularly, I hope to dissuade you from buying a new puppy or kitten directly from a breeder or kennel or retail shop.

Why not? One reason overrides all others. Every deliberately bred animal that moves into a home preempts a place needed by a deserving orphan that may not otherwise survive. So purchasing a pedigreed pet not only does nothing to reduce the numbers of homeless that are put to death every year, but actually perpetuates them.

Let’s touch briefly on the reasons why people do seek purebred dogs. (The situation of purebred cats is somewhat different.)

Snob appeal seems harmless enough. But it can turn tragic when a fashionable breed falls out of favor or the dogs themselves prove too challenging for the faddists to handle. Then, their trophy pets are dumped en masse into the shelters. Such was the fate of the Chow Chow and, more recently, the Dalmatian (from thousands of disillusioned owners who had been enticed by the Disney movie “101 Dalmatians”). Some observers think it may now be the turn of the Rottweiler and the cocker spaniel, both of which still rank among the top ten breeds registered by the American Kennel Club (AKC).

At the opposite pole from the status symbols are the breeds valued for their service role. The work such dogs perform is admirable. It also perpetuates their true and noble heritage – the development over the centuries of different breeds of dog for hunting, herding, tracking and other vital tasks serving their human companions. Today we see dogs specifically qualified for search and rescue missions, assisting the disabled, guarding livestock, aiding police and drug and bomb and arson squads, locating victims buried by earthquakes, providing therapy for hospital and nursing home patients, even alerting epileptics to impending seizure.

By no means need these working dogs all be purebred. A Labrador-golden retriever cross, for example, has proved to be one of the most successful guide dogs for the blind. The San Francisco Society for the Prevention of Cruelty to Animals (SPCA) pioneered the training of mixed-breed shelter animals as “hearing dogs” to aid the deaf. Organizations such as Canine Companions for Independence and the Delta Society regularly recruit former strays – some of which are then trained by prison inmates – for careers as service and assistance dogs.

Still, the special talents of some traditional breeds are rarely surpassed. Few dogs can herd sheep as well as a border collie, track a missing person as well as a bloodhound, serve as a police dog or army scout as well as a German shepherd. And since 1984, when the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service organized its Beagle Brigade, passengers arriving at international airports have encountered many of these alert little scent hounds in their official green vests as they patrol for forbidden foodstuffs. I myself have more than once been “arrested” when a beagle planted itself next to my hand baggage, announcing the presence of concealed fruit to its handler.

A particular breed of dog trained for important work is free to become a full-time pet only if it fails to make the grade professionally or when it eventually retires, often to live with its handler. Thus few of these animals are available to the general pet-owning public, which in any case has little incentive to seek them out.

If at least four out of five purebred dogs are indeed destined to be “solely and entirely family pets,” as the AKC official told me, how do they really differ from mutts in the hearts and minds of their owners? Put another way: Why would someone who is not a status snob, who does not need the skilled services of a working dog, and who is not likely ever to participate in dog shows or other competitions bother to buy an expensive purebred in the first place?

The reason most owners give is simple enough. They want a certain predictable look in their pet – size, shape, coat, color, features – with a predictable personality that goes with the breed. I have one friend who likes only dachshunds; another is hooked on poodles; another is partial to wirehair fox terriers; others, such as the neighbor I mentioned earlier, will keep nothing but Labrador retrievers – all quite natural and understandable. We have markedly different, often strong, preferences in food and fashion, art and furnishings, books and movies and music and most everything in our lives that’s a matter of personal taste. Why not in our choice of dogs?

What puts dogs in a special consumer category is, of course, their needs as living creatures. Can we afford to indulge our preferences for particular breeds without condemning other, random-bred dogs to death and contributing to the oversupply of homeless? Yes, indeed we can – by making a few compromises when we set out to seek our new pet. But before discussing how, let’s look at some basic facts about purebred dogs.

First, how many are there? The AKC claims that at least a third of all pet dogs in the United States are purebred, and few others contradict this. The calculation goes roughly: To the number of dogs – between 12 million and 15 million – individually registered with the AKC, the nation’s (and the world’s) biggest purebred registry, should be added another 6 million or so registered with the United Kennel Club and other, smaller organizations. This yields a registered-purebred figure in the neighborhood of 20 million, out of a national total of over 58 million owned dogs. But – a significant but – about half of the puppies purchased from AKC-registered litters have no individual registration papers, because their new owners never bothered to obtain them. So adding the pets eligible but not registered to those which are registered actually doubles the number of AKC dogs and raises the proportion of purebreds to half or more of our total pet dog population. This jibes with responses to a 1998 survey of pet owners by the American Pet Products Manufacturers Association (APPMA). On average, slightly more than half of all their dogs were purebred: 53 percent in the seven-out-of-ten households owning only one dog; 57 percent when two dogs were owned; 41 percent when three or more dogs were owned.

Next, where do all these purebreds come from? There are four principal sources. Large-scale commercial breeding operations – the notorious “puppy mills” – are located predominantly but not exclusively in Midwestern farm states. These puppies are distributed through wholesale brokers to retail pet shops around the country. (However, the 1998 APPMA survey showed that only 8 percent of all the dog owners’ pets had been acquired from stores – contrasted with the 29 percent obtained from breeders. This suggests, but of course doesn’t conclusively prove, that the impact of the puppy-mill producers may be somewhat exaggerated in the propaganda of humane organizations.) In addition to retail shops, there are also some large commercial kennels which sell their puppies directly to the public.

Less structured, but no less commercial, is what the dog fancy contemptuously terms the “backyard breeder.” This is the individual dog owner who mates his registered purebred with another pet of the same breed. The stud fee, or the proceeds from sale of the puppies, allows him to recoup the price of his own dog, ideally with some added profit. Some backyard breeders do this just once or twice before having their pet altered. Others allow it to occur accidentally, resulting in first-generation mongrels. In no case is there any attempt at quality control. The best that can be said for the backyard breeder’s product, compared with the puppy mill’s, is that at least these puppies are born, nurtured and initially socialized in a home environment.

The fourth source of purebred dogs – the only one recommended by the AKC, the dog fancy in general, most veterinarians and other experts – is what is often called a “responsible” breeder. Other approving adjectives for the same activity include “professional,” “conscientious,” “reputable,” “private” or “hobby” breeder. Some advertise in the classified columns of local newspapers and magazines like Dog World and Dog Fancy; others rely on word of mouth for their customers. Some are manifestly more responsible, professional, etc. than others.

A thumbnail sketch of the best kind of breeder starts with the fact that she (most are women) is working at it not for the money, but to sustain and improve the quality of a type of dog she loves. She specializes in that one breed, or two at most, and is a member in good standing of its national breed club. Her home-based kennel operation is small. Her puppies are hand-raised, scrupulously observed and socialized. She won’t overbreed, producing just a few litters a year. Ideally, she doesn’t breed at all until she has a waiting list of carefully screened customers for the puppies. Whenever she sells her “pet quality” puppies – those not meeting the rigorous breed standards for championship shows or competition – she requires them to be spayed and neutered, as a stipulation in the contract of sale before releasing them to their new families. She takes pains to educate first-time owners on the care and characteristics of the breed, and remains available for her customers to consult about any problems. The responsible breeder, moreover, stays responsible for each of her puppies for its lifetime. If its first place doesn’t work out for any reason, she guarantees to take the dog back or find it a new home.

Yet even the most conscientious of breeders can’t reverse years of decline in the quality of many purebred dogs. Nor can they, or anyone else in the dog fancy, prevent millions of purebreds from ending up every year on the discard pile of throwaway pets.