The biggest difference between the American bulldog and the pit bull is their heads and snouts. The pit bull has a large block head and a longer snout than the American bulldog. The American bulldog's head is rounder, and the snout is tapered and short.
The pit bull's lineage extends from a long line of terrier breeds, while the American bulldog is a descendant of the mastiff and bullmastiff families. Because of their link to the mastiff line, American bulldogs have skin wrinkles on their foreheads, while pit bulls do not. In general, the pit bull is smaller and stockier than the American bulldog.