This does not mean that they are not purebred Chihuahuas; they do not meet the requirements to enter a conformation show. Oversized Chihuahuas are seen in some of the best, and worst, bloodlines. Chihuahuas do not breed true for size, and puppies from the same litter can mature drastically different sizes from one another. As well, larger breeding females are less likely to experience dystocia. Typically, the breed standard for both the long and short coat chihuahua will be identical except for the description of the coat.[14] Chihuahuas have large, round eyes and large, erect ears, set in a high, dramatically rounded skull.