The Boxer is a medium to large, short-haired dog breed of mastiff-type, developed in Germany. The coat is smooth and tight-fitting; colors are fawn, brindled, or white, with or without white markings. Boxers are brachycephalic (they have broad, short skulls), have a square muzzle, have mandibular prognathism (an underbite), have very strong jaws, and have a powerful bite ideal for hanging on to large prey. The Boxer was bred from the Old English Bulldog and the now-extinct Bullenbeisser, which became extinct by crossbreeding rather than by a decadence of the breed. The Boxer is a member of both The Kennel Club and the American Kennel Club (AKC) Working Group.