Dog breeds are defined as groups of closely related and visibly
similar domestic dogs. All dog breeds are members of the
subspecies Canis lupus familiaris and all have characteristic
traits that are selected and maintained through breeding by
humans. A given dog breed is bred from a known foundation stock.
The term dog breed also refers to those natural breeds
(landraces) which developed naturally over time in response to
particular environmental factors, which included their
association with humans, but with little or no selective
breeding by humans. Such undocumented breeds are identified by
their appearance and, most often, by the type work they do. The
ancient dog breeds represent some of the modern, and now
documented, descendants of these natural breeds. It surprises
many that dog breeds are not actually scientifically defined
biological classifications. They are, rather, groupings
designated by clubs of hobbyists known as breed clubs. The
naming of a dog breed is considered when by a sufficient number