Toy dog term teacup dog, thus the toy/teacup boundary remains fuzzy. The standard size for a toy dog ranges from 4 to 7 pounds; anything smaller than the standard size of a toy dog may be a runt of a litter. No official size defines a teacup dog, but unofficially a teacup dog is considered to be a dog that is 17 inches or less and weighs 4 lbs or less at the age of 12 months. There are no specific teacup dog breeds, but popular types for breeding teacup dogs include: Shih Tzu, Chihuahua, Yorkshire Terrier, Poodle, Pug, Maltese, Pomeranian, and
Dog breed the other European dogs despite reports of direct Scandinavian origins dating back 5,000 years. The dog which accompanied the ancestors of Native Americans from Siberia is extinct. The spread of modern dog breeds has been difficult to resolve because many are the products of the controlled breeding practices of the Victorian era (1830–1900). In 2010, a study looked at 48,000 Single nucleotide polymorphisms that gave a genome-wide coverage of 912 dogs representing 85 breeds. The study found distinct genetic clusters within modern dogs that largely corresponded to phenotype or function. These included spitz-breeds, toy dogs, spaniels, Mastiff-like breeds, small terriers,