Human hunter-gatherers and wolves experienced several overlaps as both are social species, they shared habitat and hunted the same prey. There are several theories to explain possible routes for domestication of the dog:
1. Orphaned wolf-cubs: Studies have shown that some wolf pups taken at an early age and reared by humans are easily tamed and socialized. Once these early adoptees started breeding amongst themselves, a new generation of tame "wolf-like" domestic animals would result which would over generations of time, become more dog-like.
2. The Promise of Food/Self Domestication: Early wolves would, as scavengers, be attracted to the bones and refuse dumps of human campsites. Dr. Raymond Coppinger of Hampshire College, Massachusetts, argues that those wolves that were more successful at interacting with humans would pass these traits onto their offspring, eventually creating wolves with a greater propensity to be domesticated. Coppinger believes that a behavioral characteristic called "flight distance" was crucial to the transformation from wild wolf to the ancestors of the modern dog. It represents how close an animal will allow humans (or anything else it perceives as dangerous) to get before it runs away. Animals with shorter flight distances will linger, and feed, when humans are close by; this behavioral trait would have been passed on to successive generations, and amplified, creating animals that are increasingly more comfortable around humans. "My argument is that what domesticated-or tame-means is to be able to eat in the presence of human beings. That is the thing that wild wolves can't do."Hypothetically, wolves separated into two populations - the village-oriented scavengers and the packs of hunters. The next steps have not been defined, but selective pressure must have been present to sustain the divergence of these populations.
3. As a beast of burden: North American Indians used dog-sized travois before adapting the horse for this purpose, and huskies are famous for pulling sleds for Inuit communities. It is very probable that the dog was the original beast of burden before the domestication of the horse or ox.
4. Dogs as a source of food and fur: Whilst Westerners have difficulty thinking of dogs (or wolves) as a source of meat, wolf fur is a highly prized commodity.
Archaeology has placed the earliest known domestication at potentially 12,000 BC-10,000 BC and with certainty at 7,000 BC. Domestication of the wolf over time has produced a number of physical changes typical of all domesticated mammals. These include: a reduction in overall size; changes in coat coloration and markings; a shorter jaw initially with crowding of the teeth and, later, with the shrinking in size of the teeth; a reduction in brain size and intelligence and thus in cranial capacity (particularly those areas relating to alertness and sensory processing, necessary in the wild); and the development of a pronounced “stop”, or vertical drop in front of the forehead (brachycephaly). Behaviorally, the wagging of tails and barking are behaviors only found in wolf puppies, retained via neoteny throughout the dog's life. Certain wolf-like behaviors, such as the regurgitation of partially digested food for the young, have also disappeared.
[From Wikipedia.]
