Pedigree Project

The dog, Canis familiaris, is a direct descendant of the gray wolf, Canis lupus:  In other words, dogs as we know them are domesticated wolves. In addition to changed behavior; domestic dogs are different in form; smaller with shorter muzzles and smaller teeth.

The evolution of domesticated dogs is not well documented, as the process has been going on long before recorded history.  We get some clues about the evolution from artwork of primitive peoples around the world, where there were obvious images of dogs included in the primitive art, and more recently definitive evidence comes from DNA analysis.  Numerous archaeometric approaches have been applied to document the interaction between wolves, dogs, and people in order to establish the time frame and geography of dog domestication.  These studies have shown, first that dogs were the earliest animal domesticated, and the only species that entered into a domestic relationship with people during the Pleistocene

Molecular evidence, published in 1997, shows that dogs are descended from the gray wolf, and were domesticated about 130,000 years ago. How this domestication happened has been a matter of speculation.  Until recently general thought was that dogs were wild until about 12,000 years ago.  This means that wolves began to adapt to human society long before humans settled down and began practicing agriculture.

Archeological evidence for co-existence of dogs and humans, but not necessarily
domestication, comes from Upper Paleolithic sites in Europe. These hold
evidence for dog interaction with humans and include Goyrt Cave in Belgium, Chauvet cave in France, and Predmosti in the Czech Republic. European Mesolithic sites like Skateholm (5250–3700 BC) in Sweden have dog burials, proving the value of the furry beasts to hunter-gatherer settlements.

Danger Cave in Utah is the earliest known case of dog burial in the Americas,
at about 11,000 years ago, likely a descendant of Asian dogs. Continued
interbreeding with wolves, a characteristic found throughout the life
history of dogs everywhere, has apparently resulted in the hybrid black wolf found in the Americas. Black fur coloration is a dog characteristic, not originally found in wolves.

The earlier timing casts doubt on the long-held myth that humans
domesticated dogs to serve as guards or companions to assist them.
Dogs may have exploited a niche they discovered in early human society and got humans to take them in out of the cold.  Darwin was wrong about dogs. He thought their remarkable diversity must reflect interbreeding with several types of wild dogs, but the DNA findings say differently. All modern dogs are descendants of wolves, though this domestication may have happened more than once, producing groups of dogs descended from two unique common ancestors, the European gray wolf and the Asian wolf.

But if they all share a common ancestor, why do toy poodles and Great Danes seem to have little in common? Years of selective breeding by humans has resulted in the artificial “evolution” of dogs into many different types.