A mongrel is a dog of mixed or uncertain breed, combining traits from different types of dogs rather than being a purebred like a Golden Retriever or German Shepherd. If a Labrador and a Beagle have puppies together, those puppies are mongrels. Many beloved family dogs are mongrels, sometimes called mixed breeds or mutts.

Interestingly, mongrel dogs often turn out healthier and hardier than purebreds because they inherit a wider mix of genes. A purebred dog might face health problems that come from generations of careful breeding, while a mongrel may benefit from genetic variety.