* Smallest by height: The Chihuahua is generally considered the smallest dog breed by height. They can stand as low as 5 inches tall.
* Smallest by weight: The Chihuahua also typically holds the title for smallest by weight, with some weighing as little as 2 pounds.
* Smallest overall: While the Chihuahua is typically considered the smallest, there are other breeds that can be even smaller. For example, the Yorkshire Terrier can be as small as 4 pounds, and the Pomeranian can be as small as 3 pounds.
It's important to remember that these are just general guidelines. The size of an individual dog within a breed can vary depending on its genetics and upbringing.
Ultimately, the "littlest dog type" is a matter of perspective and the specific criteria you're using to measure size.