Since then, the Springer and Cocker enthusiasts have bred in the separate traits that they desired. Today, the breed differ in more ways than weight alone. Today, the breed differ in more ways than weight alone. The American Cocker Spaniel was developed from the English Cocker Spaniel in the 19th century to retrieve quail and woodcock. They were originally divided from the English Cocker solely on a size basis, but were bred over the years for different specific traits.