Typically, the breed standard for both the Long and Smooth coat Chihuahuas will be identical except for the description of the coat.Both the Smooth and the Long Coats have their special attractions and are equally easy to keep clean and well-groomed. The term smooth coat does not mean that the hair is necessarily smooth, as the hair can range from having a velvet touch to a whiskery feel. Although a Teacup is much smaller in size, they still have the same confident and energetic personality as a full-sized Chihuahua. It is also very risky for Teacup Chihuahuas to have puppies due to their size. The knee cap sliding across the bony ridges of the femur can cause some pain. The affected chihuahua will hold its leg flexed, and foot off the ground until the quadriceps muscle relaxes and lengthens, after which the animal feels no discomfort and continues with activity.