Dog

Dogs, colloquially known as "man's best friend", are a subspecies of wolves (given the scientific name Canis lupus familiaris), divided into a multitude of different breeds all capable of interbreeding (though in some cases, physical relations between representatives of two breeds are unlikely or problematic - Chihuahuas and Great Danes, for example). They are one of the most well-known domesticated species, with archaeological and historical records showing that they have lived in a mutually beneficial relationship with humans for upwards of ten thousand years; in Biblical times, they had already been coexisting with humans long enough for it to be regarded as the natural order of things.

It is likely, based on genetic evidence, that the oldest breeds of dog originate in Asia, and that thus the domestic dog originated there; similar research has shown that it is probable that the first settlers of the Americas brought dogs of some sort with them.

Today, dogs are valued for many different uses; companionship is chief in the United States. Their predatory origin gives them value as guard animals, while their intelligence and natural tendency towards pack psychology makes them invaluable as service animals for the disabled, as well as a potent tool (with their truly impressive sense of smell) for law enforcement officials.

Dogs have also historically been used for aid in hunting (whether as an actual attack animal or simply to retrieve downed game), transportation (the Iditarod is a good example of dogsledding), or even as food - a practice today frowned upon by most of the western world, given their degree of interdependency with humans (as well as high intelligence and friendly nature).