It’s helpful to know about dog breeds and what is a dog breed before deciding to adopt a new puppy. Dog breed goes beyond cute puppy looks, and can help owners choose the perfect match. Dog breed refers to a distinct type of dog that has predictable physical and/or temperament characteristics that can be consistently reproduced in that dog's offspring. In other words, a mom-dog and daddy-dog of the same “breed” will have puppies that look and act like they do.
What Is A Breed?
A dog of a particular breed has a known, traceable ancestry referred to as the pedigree. A pedigreed or "purebred" dog is one produced by mating a male and female dog of the same breed. Registering the litter produced from such a breeding authenticates breed status of those puppies by placing them on record in a dog registry association. There are over 400 distinct dog breeds recognized around the world.
How Do Breeds Develop?
Dogs have been associated with humans for at least 15,000 years, with recent genetic research pointing to as early as 100,000 years ago. Dog “types” like the Alaskan Malamute and Saluki appeared in nature, and changed very little over the centuries. Many of the breeds we know today have been around for 3000 years or longer and selective breeding by dog fanciers refined these breeds.
Dog looks and behavior evolved when people selectively bred dogs to suit their needs—to improve herding or scenting ability, for example. Breeders still experiment by creating hybrids and designer dogs. In the past when a new “type” appeared through an accidental breeding or mutation, early people promoted it.
"Spontaneous mutations" are accidents of nature that change the look or other aspects of the dog. Happy accidents include body shape and size, ear placement and tail carriage, scenting and sighting ability, or even hair coat and color. Despite the great variety in size and shape, all dogs are easily recognizable as canines. Dog breeds range in size from teacup sizes, to pony-size 200 pound plus canines.
Giantism (acromegaly) mutation created breeds like the Great Dane and St. Bernard. These mastiff-type breeds not only are larger, they tend to be more heavily muscled and cobby—have a compact, short-bodied structure. By comparison, sighthound breeds like Greyhounds are no less muscled but appear more lithe -- and there are a wide range between the two extremes.
Small breeds developed when a normal-sized dog simply miniaturized. The Whippet, for example, looks like a scaled down Greyhound, while the Poodle comes in three sizes including the tiny Toy Poodle. It may be hard to believe, but the Pug is a mastiff-type and so is the Chihuahua, often with a similar attitude as their larger counterparts.
The other “little” dogs aren’t always so small—but instead, simply short. Dwarfism (achondroplasia) results in shortened, somewhat curved leg bones but leaves the body proportional. Examples include breeds like Dachshunds, Basset Hounds and Corgies.