Adopt a mixed breed dog from the Humane Society and gain a friend; save a life. Heinz 57, mutt, mongrel or “All American” are names often used to define mixed breed dogs. These dogs are not purebred and a challenge to guess their heritage unless the parents are available to offer hints about their background. The term “All American” works for the mixed breed, just as many people here in the US are proud of their various backgrounds. A person adopting a mixed breed dog is willing to take a gamble.