How does the modern standard weight of a Yorkshire Terrier compare to the original working dogs?

The modern standard weight limit of 7 pounds is smaller than the original dogs, which weighed closer to 10 or 12 pounds

The evolution of the Yorkshire Terrier demonstrates a dramatic impact of selective breeding within the *Canis lupus familiaris* subspecies regarding size. The original dogs developed in Victorian England for ratting in mills and mines were physically larger, often weighing around 10 or 12 pounds. In contrast, the modern standard for the breed has been intensely selected toward miniature stature, typically requiring the dog to weigh no more than 7 pounds. This significant reduction in size illustrates how human preference for a companion animal aesthetic over ancestral working function can lead to such extreme divergence within a single established subspecies, resulting in a much smaller contemporary dog.