ILLUSTRATION BY CHRIS BUZELLI
Purebreds don’t satisfy the biological definition of a species.
What is a dog? Many people often think of dogs as kennel club creations. The purebred dog is man’s best friend, not the street dog. Man’s best friends live ubiquitously in the United States, Europe, and other developed countries and, in these countries, are by and large household pets. Man’s best friends only live in areas where people have easy access to vaccines against rabies and distemper. They are the results of certain levels of commercial appeal involving pet stores, breeders, dog food companies, veterinary medicine, magazines, and books.
But could it be that breeds represented as working, hunting, or pet groups don’t represent real dogs? Could it be that the so-called stray dogs, street dogs, neighborhood dogs, village dogs, and even feral dogs of the world are the real, naturally evolved, self-selected dogs?
When watching the dogs in the Mexico City dump, a number of our students would say, “These dogs are different from real dogs—these are mongrels.” The implication is that the kennel club breeds are the ancestors of the village dogs. People seem to believe that if a dog doesn’t look like one of the kennel club recognized breeds then it must be a hybrid or mongrel. People think if you let all the pure breeds go and they interbreed for a few generations, the resulting population of dogs would look like the Mexico City dump dogs.
However, this cannot be true. For instance, dogs on the East African Island of Pemba all look the same, and they have never been anywhere near any breed of dog. Breeds of dogs are a result of what Darwin labeled artificial selection, which he contrasted with natural selection. He was impressed with, even in awe of, people who created breeds of pigeons or dogs or the myriad of farmyard species. Darwinian artificial selection happens when humans select for a particular trait by sexually isolating a male and a female from the general population. Modern humans with their chain-link fences and wire cages find that isolation fairly easy to do, which is why most of the greatest number of breeds of dogs or breeds of anything are relatively recent. Thus, artificial selection enabled the purposeful creation of most of our present breeds of dogs.
Could it be that breeds represented as working, hunting, or pet groups don’t represent real dogs?
Numbering only about 15 percent of the world’s population of dogs, the purebreds, if left to mingle with a free-ranging population, are not going to have any effect on the genetic structure of the world population of dogs. If you released those 150 million purebred dogs into the wild all at once, they would not survive for very long. Why? They aren’t adapted to any ecological niche, and their numbers would be rapidly swamped by the 850 million village or street dogs, either by not finding adequate food or by crossbreeding with the wild dogs.
Our beautiful village dogs are neither the result of artificial selection nor the result of mongrelization of stray pet dogs. The similarity in size and overall design of all the street dogs and village dogs should give you a clue—a clue about natural selection…