Our domestic dogs, those furry creatures who play with us, walk with us and curl up next to us on the couch, evolved from the wolf, Canis lupus, many thousands of years ago. Although the earliest dog fossils date from 12,000 to 17,000 years ago, DNA studies suggest that Canis familiaris branched off from the wolf well over 75,000 years ago.
These DNA studies also indicate that dogs evolved in many different parts of the ancient world, and that they continued to interbreed with wolves even after they were domesticated by man. Even though there are significant physical differences between dogs and wolves, and in fact between individual dog breeds, there is actually very little genetic variation between most members of the Canis family.
During the late Mesolithic period (around 12,000 BCE) when wolves became domesticated, humans lived as hunter-gatherers, moving from place to place in search of food. The relationship between man and dog was mutually beneficial; the dog warned of approaching danger such as wild animals or other nomadic groups of humans, and in exchange, they had a more regular source food and were less likely to go hungry.
No-one is certain how the wolf became domesticated. Some argue that humans adopted wolf cubs and fed them, and because they were young, they were less afraid and less aggressive with man. Because these individuals were better fed, they were more likely to be able to reproduce and successfully rear their litter, so their offspring were also more domesticated.
Other researchers feel that the wolf initiated contact with man as they scavenged leftover food around their campsites. The less nervous dogs were more successful at this, and thus they were more likely to survive and reproduce in difficult times. This is evolution at its best – animals that are better able to adapt to their environment are more likely to reproduce and pass on their genes and therefore their characteristics to the next generation.
Soon after they were domesticated, dogs spread amongst early human populations around the globe. Dog fossils have been found in Germany, Russia and the Middle East. Even in these ancient times, man played an active role in the evolution of the dog, as over the years he specifically chose dogs that retained their puppy-like personality into adulthood, because these individual animals were less threatening. Physical puppy-like features were also important; dogs with a round head, folded ears, small body size and soft fur were considered more attractive.