The American Hairless Terrier is a small to medium-sized breed of terrier that originated in the United States. It is the hairless variety of the Rat Terrier, and was developed by breeding selectively for the gene that causes the hairlessness. The Hairless variety is considered to have a more mellow and laid-back temperament than its coated counterpart, and is an active and intelligent breed that loves to please and stay busy. The breed stands between 12-16 inches at the shoulder and comes in a variety of colors.