The mastín Español or Spanish mastiff, is a giant breed of dog from in Spain, originally bred to be a guard dog whose specialized purpose is to be a livestock guardian dog protecting flocks and/or herds from wolves and other predators. This noble giant is aloof, dignified, calm and intelligent. It is devoted to its family and may politely accept strangers if it has been socialized properly, although it will be wary of them. It can be aggressive toward other dogs. The Spanish Mastiff may be a less-than-ideal pet in urban situations, where its booming voice and massive size could be problematic. It is a wonderful protector of its home and family.