Your dogs temperament should match yours. Do not choose a breed that is highly energetic if you are a couch potato. On the other hand, if you want a dog that will follow you everywhere around the house and who is always ready for a game of fetch or tug of war then you should consider a dog that is highly active and always has a lot of energy, instead of one of the lethargic breeds.
What you may not know is that many breeds today have very small populations. If some breeds were any other kind of animal they would be considered endangered. You may find it hard to believe, but breeds can become extinct. If you read any histories about dog breeds, you will find lots of references to breeds that are gone now. Countless breeds have become extinct over the centuries. In some cases we have some of their descendants because they contributed to newer breeds, but not always. Some people might not care if particular breeds become extinct, but if you are a fan of a breed, then this might matter to you. From a genetic viewpoint, it’s always good to have a wide selection of dogs that contributed to a breed’s foundation. You never know when it might be necessary to reintroduce some of the genes from an older breed for health reasons. If those breeds are extinct, that’s no longer a possibility.
In some cases, a breeds origin overlaps the boundaries of two or more countries; the dog is normally listed only in the country with which it is most commonly associated; for example, by its designated country according to the Fédération Cynologique Internationale (FCI). Some dogs, such as the Löwchen, have an uncertain origin and are listed under several countries.
Dog breeds are dogs that have relatively uniform physical characteristics developed under controlled conditions by humans, with breeding animals selected for phenotypic traits such as size, coat color, structure, and behavior. The Fédération Cynologique Internationale recognizes 337 pure dog breeds. Other uses of the term breed when referring to dogs may include pure breeds, cross-breeds, mixed breeds and natural breeds.