Dog and Taxonomy

The dog (Canis lupus familiaris) is a domesticated subspecies of the gray wolf, a mammal of the Canidae family of the order Carnivora. The term encompasses both feral and pet varieties and is also sometimes used to describe wild canids of other subspecies or species. The domestic dog has been one of the most widely kept working and companion animals in human history, as well as being a food source in some cultures. There are estimated to be 400 million dogs in the world.

The dog has developed into hundreds of varied breeds. Height measured to the withers ranges from a few inches in the Chihuahua to a few feet in the Irish Wolfhound; color varies from white through grays (usually called blue) to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; and, coats can be very short to many centimeters long, from coarse hair to something akin to wool, straight or curly, or smooth. It is common for most breeds to shed this coat, however some non-shedding breeds are also popular.

Taxonomy

The English word dog, in common usage, refers to the domestic pet dog, Canis lupus familiaris. The species was originally classified as Canis familiaris and Canis familiarus domesticus by Linnaeus in 1758. In 1993, dogs were reclassified as a subspecies of the gray wolf, Canis lupus, by the Smithsonian Institution and the American Society of Mammalogists. "Dog" is sometimes used to refer collectively to any mammal belonging to the family Canidae (as in "the dog family"), such as wolves, foxes, and coyotes. Some members of the family have "dog" in their common names, such as the Raccoon Dog and the African Wild Dog. A few animals have "dog" in their common names but are not canids, such as the prairie dog and the dog fish.

Ref : http://en.wikipedia.org