Looking at the Chihuahua, it can be described as a dog fast in movement, with a good reaction, lively character, absolutely fearless. They are extremely mobile, inquisitive, tireless, and hardy. By temperament, Chihuahuas are friendly to people and other animals, without signs of anger and cowardice. An aggressive or overly fearful temperament is considered a disqualifying fault for the breed.
According to the breed standard, a variety of colors are possible. Chihuahua merle color is controversial and not universally recognized. Animals with this color may experience hearing and vision problems, including partial to complete deafness, increased intraocular pressure, ametropia (blurring of the image on the retina), microphthalmos (small size of the eyeball), coloboma (pupil defect), bone abnormalities, reproductive systems, and heart.