Much research is devoted to the domestication of man's best friend, the dog, which paired with humans in a very successful biological strategy. While the ancestor of dogs, the wolf, needs protection from extinction, there are nearly 400 hundred million dogs in the world. Though no one is sure exactly how dogs evolved from wolves, there are different theories that explain the pairing between two of the world's most successful species.
The benefits between a human-wolf pairing are obvious--both hunted animals much larger than themselves in small groups. Humans had the benefit of tools, while wolves had the benefit of speed and instinct. It was a good combination that has served both well. Even now, dogs help humans, whether by hunting, protecting livestock or the home, performing other service jobs or acting as companions.
The first evidence of dogs interacting with humans dates back to 12,000 years ago in Iraq; a burial site was discovered of a human cradling a puppy. This puppy had a smaller jaw and teeth than a wolf, indicating that dog domestication had already begun and this was not just a wolf puppy that happened to be friendly. Experts estimate that the process of dog domestication probably began 14,000 years ago. Excavations dated from 1 AD have shown skeletons of a dog similar to the present-day Pekingese, which is a far cry from wolf ancestors. According to Roman writers from that time, Roman ladies had lap dogs because their warmth was supposed to cure stomach aches.
Because the first evidence of dogs were found in Iraq, it is believed that dogs descended from Middle Eastern wolves. Biologists once thought that dogs descended from wolves in eastern Asia but new genetic research from scientists at the University of California at Los Angeles shows that today's dogs share more genetic markers with Middle Eastern wolves. More than 900 dogs from 85 breeds were compared with the genes of wolf populations from all over the world and most breeds shared the majority of genetic markers with the Middle Eastern wolves.
There are two distinct theories about how dogs evolved from wolves. One involves ancient people making wolf cubs into pets. Through time, these tame wolves gave birth to more tame wolves and dogs began to evolve. However, many biologist say that this theory ignores the actual concept of evolution. It ignores how dogs became genetically separate from wolves, which would involve individuals having different traits, such as smaller jaws, and only those traits being then bred. Individuals don't evolve. Populations do. If domesticating wolves caused them to change genetically, we would be able to imitate this and we haven't been able to do that.
Biologists such as Raymond Coppinger are now suggesting that dogs evolved from some wolves adapting a different feeding niche. These wolves realized that humans provided a great source of food in all the waste they left behind at hunting and living sites, such as carcasses and other leftovers. These wolves began to hover around campsites and feed only on this waste, eliminating the need for hunting. Not only did these wolves evolve to be less shy because they had to be exposed to humans but they also evolved to have smaller jaws and teeth because they no longer needed them for hunting. These wolves evolved into what are known now as dogs and were then further domesticated into pets.