Читать книгу Puppies - Amy Fernandez - Страница 7

People have recognized and enjoyed the benefits of canine companionship for thousands of years. Many historians believe this enduring bond began when ancient humans adopted and raised orphaned wolf puppies. Archaeological excavations have discovered wolf and human remains at the same sites dating back four hundred thousand years. The wolf was the first species to be successfully domesticated.

DNA evidence and physical variations between ancient wolf and modern-day dog skeletons show that the dog was a genetically separate species from the wolf at least forty thousand years ago and was definitely domesticated by fifteen thousand years ago. By the beginning of the Stone Age (circa 7000 BC), the dog had become a common feature of human settlements, whereas evidence of domesticated livestock did not begin to appear at human habitation sites until one thousand years later.

Researchers believe that the domestic dog first evolved in eastern Asia. The “parent” animals were descendants of a smaller wolf species, the Indian wolf. From eastern Asia, early dogs migrated with humans to populate the Middle East, Africa, and Europe and eventually across the Siberian land bridge to North and South America.

Scientists comparing ancient wolf skulls with today’s dog skulls have found the latter to be smaller and more rounded, with narrower jaws, shorter muzzles, and smaller teeth. These physical changes of domestication were accompanied by equally dramatic behavioral changes. The domestication process altered the wolf’s natural wariness, making the dog more trusting, curious, and tolerant of unfamiliar experiences. The ability to accept variations in diet and living conditions allowed the dog to benefit from the emerging ecological niche created by human evolution.

Domestication actually enhanced the wolf’s reproductive capability. A primary feature of domestication is the ability to breed in captivity. At least eight thousand years ago, humans began deciding which animals would be bred. Canine traits originally developed in response to natural selection were suppressed or enhanced through artificial selection. So began the evolution of specialized dog breeds.

Hunting dogs were selectively bred to be larger, smaller, faster, or stronger to better pursue different types of game. As humans became increasingly dependent on livestock and farming, dogs were adapted to new roles, including herding and guarding valuable livestock, defending a homestead in an owner’s absence, and eradicating mice and rats.

The ancestors of this trio of wire fox terriers were bred by English hunters to root foxes out of their lairs and to kill vermin.

Ancient civilizations, such as those of the Greeks, Romans, Persians, and Celts, contributed to the creation of specialized dog breeds. The forerunners of most of our modern purebreds (mastiffs, greyhounds, spaniels, and terriers) existed in some form by the Middle Ages. Hunting dogs, sheepdogs, and terriers remained vital to the survival of most of the population. Certain breeds—for instance, refined sporting dogs such as the Scottish deerhound and exotic companion breeds such as the Maltese—were primarily associated with the aristocracy.

Modern purebreds trace their roots to the formation of the first dog shows and kennel clubs in the mid-nineteenth century, when breeds were defined and categorized according to ancestry and purpose. New breeds, such as the fox terrier and the Brussels griffon, were developed; exotic foreign breeds, such as the Pekingese, were brought to public attention; and many popular breeds, such as the Irish setter, transitioned from the realm of the working dog to that of the companion dog. More than four hundred recognized dog breeds exist today.