It is generally believed that the dog was the first domestic animal in most parts of the world. In a few regions goats may have been domesticated a bit sooner, but they would be the only exceptions. The first dogs may have been brought into the human circle as long as 25,000 years ago, in the Old Stone Age, when humans lived by gathering plants and hunting animals with flaked stone implements.

Domestication, of course, does not mean merely keeping wild animals around the cave or hut. It means selectively breeding wild animals until an entirely new descendant species begins to take shape. All known breeds of dogs today are members of one species, Canis familiaris. The original ancestor of the dog was almost certainly a smallish subspecies of wolf known as Canis lupus pallipes, which is still found in southern Asia, from Israel to India. It was within that area that domestication almost certainly began.

From early times, dogs were used as objects of trade and as special gifts from ruler to ruler, thus spreading far and wide from one society to another. They appeared in Tibet and flourished there thousands of years ago; much later in history, these animals were spread from Tibet across Asia and Europe to the British Isles, and eventually all over the world. People also took dogs with them to Australia and to the islands of the Pacific. If we knew more details about the early movement of dogs we would know a great deal more about the history of early humans.

How did early peoples come to domesticate the dog? In all likelihood it was because they didn't have refrigeration. We know that Stone Age humans ate the meat of wolves. Sometimes, after they drove away a pair of wolves with a shower of stones and sticks, the hunters would probably steal the wolves' cubs and take them back to their cave, campsite, or other shelter for use as food. If the cubs were killed at once, the meat had to be eaten in a day or two, or it would spoil. If the cubs were kept alive they could be killed and eaten as needed. This is done even now in parts of Asia. In time, by keeping cubs around, our early ancestors no doubt developed a new view of the animals, or at least their children did. Wolf cubs, which are easily tamed and often behave like domesticated animals during their first six months, became at least short-term pets.

Since the wolf has shown itself to be genetically flexible, early humans were able to breed these animals, seeking to develop the traits they most prized. By the late Stone Age, a few thousand years B.C., it is believed there were already several different kinds of dogs recognizable. Some would have been companion dogs, others hunting dogs, and others guard dogs. Those distinctions are still very clear today, with a few refinements.

The Earliest Breeds

About 9,000 years ago, in Sumer at the head of the Persian Gulf, the oldest breed still recognized by us today probably emerged. It is the saluki, a greyhound-like coursing hound of enormous speed but not of great intelligence. (Coursing hounds are used to hunt running game, which they follow by sight rather than smell.) A better-known coursing hound, the greyhound, appeared in Egypt a few thousand years later; it became a pet of Egyptian nobles, was revered by the Greeks as a god or near-god, and is the only breed of dog mentioned in the Old Testament.

In eastern Siberia, the Samoyed peoples developed the dog still called Samoyed, one of the oldest breeds and one which has remained pure from its earliest beginning. It was a multipurpose dog, used for pulling sleds, guarding camps, and helping in the hunt. Today's Norwegian elkhound, Alaskan malamute, Akita, chow chow, and Siberian husky, plus the forerunners of the tiny pomeranian and a number of exotic breeds rarely seen now in North America, all developed in high northern latitudes. Northern European and Asian peoples bred these so-called spitz dogs periodically with timber wolves to increase their stamina.

Other breeds of dogs began to drift back westward from Tibet. Foremost among them was the Tibetan mastiff, which in Rome became what we now call the Neapolitan mastiff. This breed is well-known in Europe but not in the United States. (The American Kennel Club currently recognizes 130 breeds which are common in the United States; there are probably as many as 425 purebred breeds worldwide.) Mastiffs, as they emerged in the form of different breeds, reflected the various uses to which they were being put. The Tibetan, later Neapolitan, mastiff was used early on in games in the arenas of the Roman Empire. These dogs engaged in combat with one another, with other (often wild) animals, and with gladiators, fighting to the death. When the Roman legions moved north into Germany, they took somewhat subdued versions of the mastiffs with them as cattle drovers and camp guards. The wild tribes encountered by the soldiers often stole dogs from Roman camps; the stolen dogs later developed in Germany into the so-called Great Danes, (which had nothing to do with Denmark) and were used to hunt wild boar, very dangerous game. They also evolved into the Rottweiler, named for the town of Rottweil (now in West Germany), and into the Saint Bernard and Bernese mountain dogs of Switzerland. When Roman soldiers reached the British Isles, in the first century B.C., they found the wild tribes there already in possession of a form of mastiff, although how that dog got there ahead of the Romans is something of a mystery. Once again the dog provides evidence of how ignorant we are of early peoples' movements and commerce.

Mastiffs in England, possibly with some input from the Romans' Neapolitan mastiffs, were bred into dwarf form and became the muscular English bulldog, used in the sport of bullbaiting until that practice became illegal in the early 19th century. Mastiffs were also interbred with the dwarf version to produce what was known as the gamekeeper's night dog and later as the bullmastiff. This breed was developed in England in the middle to late 1800's in response to rampant lawlessness, when gamekeepers on large private estates were being attacked and even killed by poachers and trespassers. The bullmastiff (then more than now bred to be dark in color) was aggressive enough to attack a poacher, knock him down, grab his arm in its mouth, and hold him, terrified and nearly paralyzed by the pressure the dog's jaws could apply. The mastiff line, however it got to and from Tibet, has led to many other breeds as well. Mastiff blood appears in the French bulldog, the little Boston terrier, the bullterrier, and the Doberman pinscher.

Another line of dogs whose earliest ancestral forms are not really known was emerging in the British Isles—the terrier clan. In Scotland, Wales, Ireland, and England and on offshore islands like Skye, these tough little vermin-killers and small hunting dogs appeared and became popular. Seen hundreds of years ago on nearly every farm in the British Isles, they remain quite common today. The two largest types were the Airedale terrier and the Irish version, the Kerry blue terrier. On farms they helped keep down the rat, weasel, and other vermin populations, protected livestock, and were perfect little hunting dogs, besides serving as watchdogs. Terriers were fairly nondescript in the early days; only in recent years have coat style and color been considered very important characteristics of the breeds. There is only one breed in the terrier group in America today that did not originate in the British Isles: the miniature schnauzer, which is a German breed.

Hunters, Herders, and Guards

While the British and their nearest neighbors were developing handy little vermin-killing terriers, true hunting dogs were emerging on the European continent. From Spain came the Spanish dogs, or spaniels. Some of these were used to hunt ducks and other waterfowl, others to hunt upland game. The spaniels were bred into large and small versions; the larger dogs eventually became known as setters—because they would "set," or crouch, when locating their quarry. Perhaps around the 17th century, some hunting-dog strains and probably some lighter-boned mastiff descendants emerged as pointers—dogs that freeze in a standing position with nose pointing at the quarry. (Today, setters no longer set, but are trained to point like pointers.) The pointing dogs later came to include the griffons from Holland, the Weimaraners from Germany, and the Vizslas from Hungary, none very ancient breeds. They are generally multipurpose hunting dogs.

Meanwhile, in eastern Europe, in Hungary and Austria, dogs with possible Tibetan ancestry were developed, some of them to guard sheep, others to herd them. These breeds included the Kuvasz, the Komondor, and the Puli, the latter two with a strange naturally corded coat unlike anything else in dogdom.

In Roman times, perhaps as far back as 2,500 years ago, there were hounds of enormously sophisticated scenting ability throughout the Mediterranean region. They were probably the ancestors of the dogs known in medieval times as Saint Hubert's hounds and, later in England, as bloodhounds. The word "bloodhound" was apparently not used to indicate any savage propensity in the animal. It most probably came about because these highly refined hounds, with the most sensitive nose in the world of dogs, could in the Middle Ages be owned only by noblemen, or people "of the blood." From the bloodhound came another dwarfed dog, the basset hound, and later the various coonhounds of the American South and all of the other scenting (as opposed to sighting, or coursing) hounds.

As for the sight hounds, they were off on a track of their own. The ancient Egyptians had developed a few breeds besides the greyhound, such as the Pharaoh, Ibizan, and Afghan hounds. The greyhound was shrunken in size, by selective breeding, to become the Italian greyhound, a lapdog. Many other hunting dogs also were being reduced in size to become house companions—elegant little playthings for nobility and royalty—and decorative watchdogs. They were status symbols as well as companions.

While several breeds of small dogs developed from sight hounds the tallest of all dogs—the Irish wolfhound, which stands about 34 inches high at the shoulder—may have developed by mixing greyhound bloodlines with mastiff lines. Another true giant, the Scottish deerhound, also evolved, and in Russia in the early 17th century young noblemen developed the towering Russian wolfhound, known in the United States as the borzoi since 1936, to hunt wolves and other game.

Thus, in their own way, the various lines of dogs spread out across the world and evolved in each new area to fit the needs and tastes of their masters.

Still on the Job

Dogs today often serve people in ways similar to those for which the breed was originally developed. The Komondor and Kuvasz that guarded sheep on the steppes of Hungary ten centuries ago are currently being tested in the American West for guarding flocks of sheep against predators. In Australia, where livestock has traditionally been the backbone of the economy, dogs like the Australian cattle dogs and the Australian sheepdogs were developed from breeds (including the collie) that settlers brought in from the British Isles and elsewhere in Europe. They are still very much in use, and some Australian breeds, such as the blue heeler, are now at work in the American Southwest herding livestock. (However, Alsatians, or German shepherds, which were originally bred to herd sheep, came to be used somewhat differently, as Seeing Eye, police, or army dogs. They lead the blind, patrol military installations, and do the kinds of jobs that make people's lives easier and safer.)

The Doberman pinscher, an alert and powerful guard breed developed in Germany by a watchman named Louis Dobermann in the late 1890's, is still a superior guard dog, although modern breeders have worked wonders in calming the animal down and giving it a far softer personality. The Rottweiler, which became a cart-puller and guard dog in Germany, continues to serve as a police patrol dog of enormous strength and courage. Over the past ten years the Rottweiler's popularity has increased markedly in the United States, with 15 times more dogs registered in 1986 with the American Kennel Club than were registered in 1977.

Many farmers still depend on terriers to patrol their barns on the lookout for rats and mice. The fast, feisty little dogs, whose lives seem to revolve around this challenging "game," are as good at their old job as they ever were. Hunters continue to use breeds like the Labrador, golden, and other retrievers for their original tasks—bringing back downed birds from the water and other inaccessible areas. Pointers are still at work locating game, and spaniels still flush out game from cover for hunters. The Brittany, a very popular European dog that looks to be midway between a spaniel and a setter, may be found doing all-around fieldwork.

Though the bloodhound was originally a hunting animal, it was weaned away from that task a very long time ago and is used today by police agencies all over the world to track down people, living or dead. Every now and then we hear of escaped convicts or suspected criminals being "nailed" by giant bloodhounds, but the great, gentle dogs have other work they do far more often. About 95 percent of the trails followed by bloodhounds today are so-called mercy runs, looking for lost campers, missing children, confused mental patients, or anyone who can leave a trail and whose life may depend on being found. Bloodhounds are purposely bred to be gentle, since it would be counterproductive to have the dogs track down victims of mischance and then attack them once they found them.

Man's Best Friend

Some jobs may be less vigorous than hunting and tracking but are nonetheless productive. For example, lapdogs originally from China, such as the Pekingese (considered sacred by the ancient Chinese) and the pug, are familiar companion dogs, meant to provide distractions from daily worries and pressures. Other small breeds, many of them unfamiliar to Americans, serve this function all over the world. The Japanese have their chin (also called the Japanese spaniel), while the Tibetans have the Tibetan spaniel (not a spaniel at all), the Tibetan terrier (not a terrier at all), the Shih Tzu, and the Lhasa Apso to amuse and console their owners.

Recent medical research has shown that companion dogs may contribute to their owners' physical as well as psychological well-being. Generally speaking, those benefiting from dogs' companionship tend to have lower blood pressure and fewer heart attacks. Studies have also found that severely ill dog-owners tend to have higher survival rates than comparable patients without pets. It could almost be said that while we thought we were selectively breeding dogs, they were selectively breeding us, with dog-lovers outliving people not especially attracted to these companionable beasts.

All kinds of dogs, both purebred and of mixed breed, also are being used to aid the handicapped. Seeing Eye dogs are well-known, but there are other dogs specially trained to serve the hearing-impaired, alerting their owners to sounds at the door, a ringing phone, or perhaps a crying baby. Some dogs have been put to work assisting the physically disabled. People confined to wheelchairs or to bed may have canine servants that bring the phone to them, pick up things that they drop, pull them around in their chairs, and do other work fitted to their owners' needs.

Other dogs labor in the field of crime detection. Beagles are now used by the U.S. Department of Agriculture to sniff incoming baggage at airports for illegal plants and foodstuffs. With their little green USDA jackets, these government beagles are becoming familiar sights wherever international flights land on American soil. All kinds of dogs with good noses, from German shepherds to hyperactive retrievers to mixed-breed dogs are trained (at Front Royal, Va.) by the U.S. Customs Service to detect drugs in incoming baggage. Billions of dollars worth of illicit drugs have been intercepted because of the enthusiasm of these animals. To them it is a wonderful game, and they go fairly wild whenever they sense the presence of drugs in an innocent-looking piece of luggage.

Also trained at Front Royal are a group of canine detectives who do work at least as vital but must have rather more finesse. They are the bomb detection dogs. Members of a canine bomb squad fortunately lack the wisdom to be nervous, but they must be taught not to tear and rip excitedly at the cases they pinpoint. Instead, they learn to sit down quietly next to the suspicious object and whine softly. That is the signal for civilians in the area to move away and leave the professionals to their work.

Dogs that help the hearing-impaired and other handicapped people and those that detect drugs and bombs are not necessarily restricted to a few breeds, and they need not be purebred. Intelligence and a certain special temperament to suit the specific case are essential. At one time, just about all dogs leading the blind were German shepherds; now Labrador and golden retrievers are just as commonly used. For most specific tasks, some breeds will do better than others, but it is seldom necessary to have only one particular breed for a job.

To Err Is Canine

Many amusing or ironic stories have been told involving dogs at work. In one incident a few years ago, authorities suspected that a policewoman had been murdered (that is not the funny part, obviously) and buried in a park. A bloodhound was brought in that had been trained to locate bodies hidden in illegal graves. He immediately fixed on a spot in the park, and the police dug in. The bones, although they seemed somewhat large for the missing woman, were dutifully packed off to the coroner. Then the dog found another burying place and another, and a good many more as well. The park had been nearly destroyed, and some police officers were on the disability list with injured backs, before it was discovered that they had put the bloodhound to work in a burying ground for old brewery horses.

A few bad days notwithstanding, dogs down through history have succeeded in doing everything from hunting and herding to carrying ammunition to front-line troops, from baby-sitting to sniffing out drugs, from supplying support to the emotionally ill and disabled to guarding livestock and property with their own lives. In all these activities dogs find themselves still doing what they were initially bred to do: faithfully serving their human owners and companions.

About the author: Roger A. Caras is a correspondent for ABC News, exclusively covering animals and the environment. His writings on these topics have appeared in numerous periodicals and newspapers, and he is the author of more than 50 books. Among his awards is the prestigious Joseph Wood Krutch medal for "significant contributions to the improvement of quality of life."