Xoloitzcuintli pup. This is an ancient breed from Mexico that comes in toy, miniature, and standard sizes. It can be coated or hairless. The Xolo is one of the world's oldest and rarest breeds and likely the first dog of the Americas. Their name is derived from Aztec words for God and Dog. Even today some people in Mexico and Central America believe these dogs can cure or ward off ailments and evil.