There does not exist another species where the size of the breeds changes that much. We can find dogs which when they are adults they weigh a little more than a kilogram and so like others will weigh a hundred times more. The small breed’s breeders look for smaller specimens and the ones for big breeds look for exactly the opposite. For example the Yorkshire terrier, which nowadays on an average rate weights 3.5kg, in its origins they weighed the double.
Without the breeder’s intervention, we would not have such extremes. Smaller breeds many times need cesarean during birth, and bigger breeds occasionally present specific health problems –such as stomach torsion-. In general, the smallest live longer, and the biggest live less than the rate of 14 years.
In Only Dogs, we classify them in 5 categories: miniature (dogs until 5kg), small (more than 5 and until 15kg), medium (more than 15 and until 30kg), big (more than 30 and until 45kg) and giants (more than 45kg).We took not the height but the weight as a reference, due to there are particularly tall breeds like the Borzoi, which frequently overcome the 90cm to the withers range, but rarely overcome the 41kg.
Among the small breeds, we find the Chihuahua, the Pomeranian, and the Miniature Pinscher. Also, the variety Kaninchen of Dachshund is very little.
In the biggest dogs team, the English Mastiff and the Saint Bernard are the ones playing, due to they are likely to overcome the 100kg of weight. Other breeds, less heavy, usually overcome them in height. The Great Dane, define a minimum of 80cm in its standard, emphasizing that the taller, the better. The Irish Wolfhound is the tallest dog in a regular rate, with most of the specimens overcoming the 85cm of height to the withers range.