For a purebred dog and, on occasion, even a first-generation hybrid, breed-inference services often just confirm what the dog owner already knows. Sometimes a pedigree is available, tracing back through multiple generations of purebred ancestors and providing essentially complete information about the pet’s ancestry. In other cases, an owner’s extensive experience leads to correct intuition that ears that floppy together with a nose that keen must indicate complete or near-complete beagle ancestry. By contrast, when applied to investigate the ancestry of a mutt, DNA-based inference often yields surprising conclusions.