Dogs came from wolves many thousands of years ago, and branched off from the wolf population due to human intervention. Subsequently many different breeds were created from the original dog. The evolution of the dog is a perfect example of what you might call “guided selection,” or “artificial selection.” The guiding force behind the selection has been the hand of humankind. The evolution from the wolf to the dog took place very quickly compared to what usually happens in nature, and amazingly, most of the breeds alive today were created in a very short time, less than two centuries. Consider this; from the few breeds of dogs alive a couple of thousand years ago, we end up with Great Danes and Chihuahuas! Such a huge difference in two subspecies (breeds) in such a short time is truly amazing.

When does a biologist refer to two animals as separate species, rather than calling them different breeds or subspecies of the same species? This is a gray area. There are several criteria which define whether or not two animals are of the same species, being able to produce viable offspring being one of the most important ones. A husky or a German shepherd could almost be considered a subspecies of wolf. But what about a pug or a Chihuahua? It would be ridiculous to call a Chihuahua a subspecies of wolf. In a sense, it even seems ridiculous to refer to a Chihuahua and a Great Dane as being of the same species.

The biologist, when classifying species, has an analogous problem to that of the linguist who classifies languages. When a group of people splits off from another group and their language evolves, at what point should their language be called a separate (though related) language to the original, rather than simply calling it a dialect of the original language? There is no easy answer. Likewise, there is no easy answer to the question of when an animal should be called a separate species, rather than a subspecies of the animal from which it evolved. The dog is a perfect example of such ambiguity.

Imagine for a moment, that no one in the world has ever seen a dog before, and then suddenly some intrepid explorer discovers dogs in some remote area. Imagine that suddenly all of the modern dog breeds are discovered at once. I can assure you that biologists would classify most breeds as separate species. Referring to a Chihuahua and a German shepherd as members of the same species is purely a matter of convention.

Dogs have done so much for humans all throughout history and look how people treat them now, discarding them like they’re just an old worn out toy, or even worse, torturing them in laboratories! We owe a lot to dogs. Humans brought them into this world many thousands of years ago by breeding wolves. We have enlisted their aide in warfare, farm work, animal herding. They sniff out bombs and drugs. They rescue people in many situations. They guide the blind, they console the lonely. They are intelligent, sensitive, faithful, loving, and affectionate. The least we can do for the dog is to give it a comfortable home and provide it with food and love.

The Romans used to seal messages in a small clay vessel and then force a dog to swallow it. They would then send the dog off, knowing that it would track down the army to which it belonged. Upon its arrival an officer would kill the dog and cut it open to get the message. I am appalled by the cruelty of the Romans (not just to dogs but to many species) but we are no better today. Dogs are tortured in laboratories every day. Not just dogs, but many species of animals have to endure the most horrible tortures at the hands of humans. How sad it is that such atrocities occur!