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Why There's No Such Thing as a Purebred Dog
Dogs are more variable in size, shape, and temperament than any other mammal alive today. The American Kennel Club recognizes 167 dog breeds, and the world governing body of dog breeds, the Fédération Cynologique Internationale, recognizes 340 breeds (whether or not a "pure" dog breed exists is subject to debate). Despite this wide spectrum of shapes and sizes, all dogs share a common ancestor. They are all direct descendents of the Canis lupus, or gray wolf. They split off about 40 million years ago, but it's unclear when they became domesticated. At some point, wolves began to linger around humans, who eventually bred them into different forms of dogs to perform different sorts of tasks.
A study published in Current Biology found that modern dog ancestors split from wolf ancestors at least 27,000 years ago. Fossils dating back as far as 36,000 years ago hinted at the transition, with mixed features of both wolf and dog. A May 2013 study in Nature Communications reported that wolves and Chinese indigenous dogs split 32,000 years ago. Researchers used demographic analysis of different mutations in the genomes of dogs and wolves, with results indicating that dogs initially scavenged with humans.
But a recent discovery has experts rethinking this: A study in the journal Scientific Reports found the remains of what was thought to be a dog from over 31,000 years ago to actually belong to those of a wolf. Researchers used 3D imaging to compare the fossil with to other dogs and wolves, and the results suggest show the features to be more wolf than dog. This would indicate that dogs did not gradually evolve from wolves over a long period of time. Instead, dog domestication more likely took place during the Neolithic era (10,200 B.C.-2,000 B.C.), when humans has moved beyond being hunter/gathers and were already farming (around 12,000 years ago). Previous research had dogs emerging during the Paleolithic era (2.6 million years ago to 10,200 B.C.) when early man were still hunter-gatherers.
What about the whole "man's best friend" thing? The bones of a puppy and an elderly person were found buried together in Israel, in a tomb dating back 14,000 years ago. Even though dogs were domesticated long before, most of the dog breeds we're familiar with developed within the last few centuries. Many breeds have changed significantly within the past 100 years, and still evolving was the trend of "designer dogs" like the labradoodle and the puggle continues to be popular amongst dog owners.
Are you a dog lover? Do you have a favorite breed? Do you prefer purebreds or "mutts"? Do you own a rescue dog? We'd love to hear about your dogs in the comments section below! Also, if you love dogs, check out these epic dog portraits over on our sister site, Seeker Network.
The Incredible Explosion of Dog Breeds (Live Science)
"From a teacup-size Chihuahua to a Great Dane, there is an incredible amount of variety among dog breeds. But all breeds belong to a single species, so scientists have studied the breeds to better understand the workings of evolution."
Evolution of the Dog (PBS)
"Recent molecular evidence shows that dogs are descended from the gray wolf, domesticated about 130,000 years ago. But if they all share a common ancestor, why do toy poodles and Great Danes seem to have little in common?"
Wolf to Dog: Scientists Agree on How, but Not Where (The New York Times)
"Scientists have long agreed that the closest living relatives of dogs are wolves, their link confirmed by both anatomy and DNA. Somewhere, at some point, some wolves became domesticated."