TALE of the Dog

Tiny teacup poodles, massive Newfoundlands, squat bulldogs, sleek greyhounds, Mexican hairless dogs, bearded collies-dogs come in an amazing variety of sizes, shapes, personalities, and talents. Where did they all come from? And how did they get to be our best pals?

At the site of one of the earliest human settlements, Ein Mallaha in northern Israel, archaeologists found the skeleton of a woman buried 12,000 years ago. The remains of a puppy seem to be cradled in her hands. Not far away scientists discovered a man from the same period buried with two doglike animals. Dog fossils have been found in Germany, Italy, Russia, and Iraq, dating back at least 14,000 years. And some scientists who study the origins of the dog by looking at its DNA (the material genes are made of) think that dogs might go back much further, perhaps 135,000 years.

One thing we know for sure, dogs are our oldest animal friends. Before horses, cows, pigs, goats, sheep-and way before cats, which first became pets in Egypt about 5,500 years ago-dogs were part of human history.

Grandpaw and Grandma Wolf

So where did dogs come from? We know part of the answer. Dr. Jennifer Leonard, a biologist at the Smithsonian's Museum of Natural History, says that recent DNA studies leave no doubt that dogs evolved Scientists have even narrowed down the dog's "grandpaws" to a single species-the gray wolf. More amazing still, it now looks like all modern-day dogs can trace their roots back to just a few female wolves that once lived in East Asia, probably China. Over time, the descendents of these wolf "Eves" spread throughout the world. When early human settlers first came to North America from Asia, crossing the Bering Sea land bridge to Alaska sometime before 9000 BC, they brought their dogs with them.

But while scientists agree that wolves evolved into dogs, just how did such an amazing transformation take place? How could a wild wolf become a tame dog? The key is in wolves' relationship to humans.

The Wanderers

During the last Ice Age, about 60,000 to 12,000 years ago, ancient humans and wolves had much in common. They were hunters who shared the same lands and competed for the same prey. And both lived in well-organized social groups.

Wolves live in family groups called packs. Each pack member-from the leader, or "alpha" wolf, to the youngest pup-has a rank and a role in the group. Group needs come first. Pack members work together to hunt for food and raise the young. They obey the leader and respect each other's rank, and they are affectionate to one another.

Wolves are smart, too. To survive, the pack must learn from experience. Bringing down large prey requires intelligence and cooperation. Wolves use a complex communication system of body movements, facial expressions, gestures, and sounds to share information and let other pack members know what they are doing.

Away from the pack, wolves by nature are shy. Like other wild animals, they fear strangers and act with caution in unfamiliar situations. Scientists think that some ancient wolves, however, may have been a bit bolder and more curious about humans. Maybe these wolves learned there were advantages to hanging around the two-legged hunters. Stealing food from the humans was probably easy. And who doesn't like a free lunch? Perhaps people were curious about wolves, too, wondering whether these intelligent and skilled four-legged hunters could be of some use.

Biologists believe that after a long period, certain wolves became accustomed to the company of humans.

Friendly Foxes

Could the friendly, domesticated dogs we know and love really have come from fierce, wild wolves? In 1959 Russian scientist Dmitry Belyaev began an experiment to test the idea that a tame animal might be bred from a wild one. He worked with wild silver foxes, close cousins of the dog that had never been domesticated. For 26 years, Belyaev chose to breed only the foxes in each litter that were the friendliest and least afraid of people.

Gradually, Belyaev created a group of foxes that acted more like pet dogs than wild foxes. To his surprise, they also showed the same physical changes-curly tails, droopy ears, and different coat colors-seen in domesticated dogs.

They grew less fearful and less wild. Some of these "tame" wolves may have moved from place to place with our nomadic ancestors, not on a leash, but free to come and go as they pleased. Our ancestors may have occasionally adopted orphaned wolf pups from this group or even stolen pups from their dens, then reared these pups by hand and tamed them, choosing the gentlest and most docile to serve as hunting companions and pets.

Who Let the Dogs In?

Most scientists believe that it wasn't until about 12,000 years ago, as the Ice Age drew to a close and our ancestors began to give up their wandering ways to settle down in permanent communities, that these tame wolves evolved into dogs. Again, it was food that may have brought humans and wolves closer together. Like modern city-dwellers, ancient humans produced a lot of waste. For the wolves, human trash heaps were a kind of all-you-can-eat buffet. It was the village dump that really "split the wolf family in two," says Professor Ray Coppinger of Hampshire College. He believes that the wolves that eventually evolved into dogs were the ones that started hanging around human garbage dumps on a permanent basis. It was these roving disposal squads that villagers tamed and bred to become dogs.

Curly Tails and Floppy Ears

Domestication-the process by which animals are changed to fit into human society-takes a long time. Humans gradually domesticated wolves through selective breeding. When our ancestors found a wolf whose behavior or looks they liked, they kept it and mated it with another wolf that had the same desirable features. With luck, pups would be born with their parents' good qualities.

According to animal behaviorist Dr. Ann Squire, "The first thing people looked for when they began to domesticate the wolf was an animal that was willing to accept a person as top dog (or alpha wolf). A wolf that refused to share its catch with humans, for instance, wouldn't be much help as a hunter." She also says that for the same reasons, our early ancestors probably chose to breed wolves that appeared less threatening-ones that were smaller than average in size and had smaller teeth.

After many generations, these domesticated wolves started to look very different from their wild cousins. Compared to their wild wolf ancestors, these dogs had smaller skulls, brains, and teeth. The process of domestication also brought about other physical changes. Tails curled. Ears flopped. Coats changed colors. And domesticated dogs, unlike adult wolves, barked.

Most important, domesticated dogs behaved differently than the wolf, enabling dogs to thrive in human society and serve as useful companions.

Dogs with Jobs

Once people learned how to selectively breed dogs, we began to create canines that came in different sizes and shapes to do many jobs.

Hunting was an important job, and dogs were bred to specialize in different hunting tasks. Tracking prey through dense forests required animals with a keen sense of smell. Bred for the ability to follow a scent trail, a bloodhound's tracking skill is legendary. But in flat, open country, where humans hunted fleet-footed prey, swift, lightweight dogs with keen vision were needed. Greyhounds and Afghan hounds are descendents of dogs bred for this purpose. Terriers were bred as pest specialists to go after small prey, such as the rats and weasels that infested villages and farms.

When sheep and goats were domesticated about 10,000 years ago, dogs helped guard and herd them. To protect their sheep, farmers needed dogs that were bigger and fiercer than wolves. They bred dogs called mastiffs weighing as much as 200 pounds. To herd livestock, farmers looked for dogs that displayed some, but not all, of the hunting instincts inherited from their wolf ancestors. When wolves hunt, they round up herds of animals, then separate the weak or ill from the group so they can attack them. Farmers needed animals that would round up but not attack their flock. Collies and Shetland sheepdogs are examples of dogs originally bred for this purpose.

Just Friends

Today, specially trained dogs-such as guide dogs for the blind and hearing ear dogs for the deaf-help people in many important ways. But most modern dogs don't have a "job." They're not hunters or herders or be guard dogs; they're just friends. Unlike their wolf ancestors, modern dogs could not survive on their own in the wild. But all dogs are still part wolf on the inside-even if they look like Chihuahuas or beagles or collies or mixed breeds on the outside. Their human family is their pack. They depend on us for food, shelter, and companionship. And they look to us as leaders of the pack.

Whether purebreds or mutts, working dogs or pampered pets, today's dogs have traveled a long way since their ancestors parted paths with the wolf. Somewhere on that journey, they left their paw prints on our hearts.

Copyright Carus Publishing Company Apr 2004
Provided by ProQuest Information and Learning Company. All rights Reserved