The Evolution and Domestication of Dogs

The Evolution and Domestication of Dogs

About 1 million years ago in the Pleistocene period the wolf had evolved to look like the wolves we know today, and around 15,000 years ago it is believed that man domesticated the wild dog. "Scientists believe that wolves are the direct ancestors of today's domestic dogs. They think that early humans domesticated wild wolves to make them useful companions and work animals. Since that time, selective breeding has produced the many varieties of domestic dogs, some of which are very un-wolflike in appearance and habit"(Johnson). Selective breeding was used by selecting phenotypic traits like coat color, structure, size, and behavior depending on the country or geographic region. No other species of animal has the wide range of phenotypic diversity as seen in canids.

The modern domesticated dog is closely related to Canis Lupis, the Grey Wolf. Through selective breeding humans have been able to manipulate the genes of dogs to create the wide variety of breeds we have today. Selective breeding is the process of breeding an animal for a particular genetic trait. Breeders have been "perfecting" different breeds for all sorts of different physical features and activities. For centuries dogs have been selected for their different characteristics; Grey Hounds were bred for speed, Collies were bred for herding, Basset Hounds were bred for hunting, and Xoloitzcuintle, known as the Mexican hairless dog, were bred to be used as heating pads on a cold night. Traits favored by the breeders may or may not be naturally favorable to the animal. For example, The English Bulldog demonstrates how breeding for looks can have a negative outcome. The English Bulldog was bred for the sport of bull baiting, where the dog would attack and hold on to the neck of a bull. In the mid 1800's, the offensive 'sport' of bull baiting was banned, but the dogs still retained their bull fighting characteristics, including large heads, body shape, and powerful jaws. The Bulldog Club accentuates these physical features, stating that the head of the dog should be as large as possible. To win at shows, bulldogs are bred for larger and larger heads. The act of increasing larger heads in bulldogs causes many bulldog puppies to be born by C-section, because the pup's head will not fit through the mother's birth canal. This is not a trait that would have been natural selected in the wild but with the aid of veterinary medicine, it's possible to select an animal with these qualities.

"Current research indicates that domestication, or the attributes of a domesticated animal, can occur much more quickly than previously believed, even within a human generation or two with determined selective breeding. It is also now generally believed that initial domestication was not attained deliberately by human intervention but through natural selection" (Dog). Wolves that scavenged around human inhabitants received more food than their more wary

counterparts. Those who attacked people were probably killed, while those more tolerant survived, and so on. This quick evolution of domesticated dogs from wolves is an example paedomorphism, which is the retention of juvenile characteristics. As with many species, the pups are more social and less dominant in comparison to adults. Therefore, the docile and "cute" characteristics of juveniles are more desirable traits for dogs in adulthood in comparison to a dog who is similar to a wild adult wolf. Compared to wolves, many adult dog breeds retain puppy like characteristics like soft fuzzy fur, round torsos, large heads and eyes, and ears that hang down rather than stand erect. A perfect example of domestication of a wild animal over time would be the foxes in Russia who are being tamed by scientist. Scientists at a breeding farm in Siberia, Russia, created a different form of the silver fox by allowing only the friendliest of the batch to breed. The program was started by Dr. Belyaev who believed that the key factor for the domestication of dogs was their behavior. He started trials with a population