What is pit bulls ethnic background?

Pit bulls, often used as a blanket term for dogs resembling the American pit bull terrier or the American Staffordshire terrier, descend from dogs historically used in bull-baiting, dogfighting, and other inhumane bloodsports. Over time, selective breeding created distinct breeds with mixed pit bull-type dogs, possessing strength, courage, and tenacity of their ancestors, but also bred for sweeter temperaments.