While the exact origins are a bit murky, there's general agreement that they are a mix of various terrier breeds, including:
* American Pit Bull Terrier: For strength and tenacity.
* Fox Terrier: For hunting ability and intelligence.
* Whippet: For speed and agility.
* Manchester Terrier: For size and coat type.
The Rat Terrier wasn't officially recognized as a breed by the American Kennel Club until 2000, but their history and usefulness as working dogs predate this formal recognition.