The dog is a canine
omnivorous mammal that has been domesticated for somewhere between
14,000 and 150,000 years. In this time, the dog has developed
into hundreds of breeds with a great degree of variation. For
example, heights ranging from just a few inches (such as the Chihuahua)
to nearly three feet (such as the Irish Wolfhound), and colors
ranging from white to black with reds, grays, and browns also
occurring in a tremendous variation of patterns. Dogs, being highly
social animals, are known for trainability, playfulness, and for
ability to fit into human households and social situations. See
dog training for details.
Dogs fill a variety
of roles in human society. Working dogs of all kinds do traditional
jobs such as herding and new jobs such as detecting contraband.
For dogs that do not do their traditional jobs, a wide range of
dog sports provide the opportunity to exhibit their natural skills.
In many countries the most common and perhaps most important role
of dogs is as companions. Dogs have lived with and worked with
humans in so many roles that they have earned the sobriquet Man's
best friend. Puppies engage in teething on almost anything.Dog,
in common usage, refers to the domestic dog, Canis lupus familiaris
(originally classified as Canis familiaris by Linnaeus in 1758,
but reclassified as a subspecies of the wolf, Canis lupus, by
the Smithsonian Institution and the American Society of Mammalogists
in 1993). The word 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. Dog is also
a term used by breeders to specifically denote a male domestic
dog. The female is known as a bitch. A young dog is called a puppy.
The words pooch and poochie are generic, generally affectionate
terms for a dog. Many additional terms are used for dogs that
are not purebred; see Terms for mixed-breed dogs.
Abpve Images Are Courtesy of the USDA