That looks like a BULL TERRIER, not a PIT BULL. Two very different breeds.
BTW... American Staffordshire Terrier, a Staffordshire Bull Terrier, Bull Terrier, and an American Pit Bull Terrier.... all are interrelated...
Here's a clip from the web:
"This was the original "Bull-and-Terrier." Crossing the 19th century bulldog with the old English Terrier produced the modern Staffordshire Bull, which still looks very much like its bull/terrier ancestor. Upon arrival in the United States in the early 1800s, the breed was crossbred to become larger and taller. The results were the American Staffordshire Terrier and the American Pit Bull Terrier. Those which remained in England retained their original form, and came to the United States about 1870, where they were recognized as the Staffordshire Bull Terrier.
During these early years, the Staff was bred and used for dog-fighting but, by the 1930s, the law had begun to make this activity disappear. Rather than see his beloved dogs vanish with their profession, fancier Joseph Dunn organized a club and worked to have this breed recognized by The Kennel Club of England. Another name besides Bull-and-Terrier had to be chosen (since the Bull Terrier had already assumed that one), so the locale of greatest interest, Staffordshire., was chosen as its dog tag.
After official acceptance in 1935, the breed's good qualities elevated these dogs to a position of popularity in their homeland, and they have retained that favor. Most Staffs brought to North America came after World War II. The breed was recognized in Canada in 1952, fol-lowed by American acceptance in 1974.
The basic difference between the Staff, AmS-taff and Pit Bull, other than size, is the fact that ear cropping is not allowed on the Staff. A folded-back "rose" or half-drop ear is required.
These dogs need activity to keep their hard-muscled physique and are happy to join their owners in jogging or other sports. Like similar breeds, they are devoted to their families, are gentle with children and accept other pets.
The Staff does require firm, consistent handling as a pup. With maturity, he is laid back, loves social contact and is a real "character." He can competently defend his own if necessary, and he knows it. Thus he rarely shows any bravura of snapping or snarling. He is quiet and calm—until needed."