The history of the Cocker Spaniel as a hunting dog of long standing is pretty well out of the picture as far as the utility of the dog in today's modern world. The English cocker has retained much more of the qualities of a hunting breed, while the American Cocker, having gained great popularity in the 60s and 70s, has gone the way of many "overbred" dogs, losing in the process some of the instinctive behaviors for which it was bred. Most probably the small size of this dog led to its demise, for it was and is an "easy breeder" and thus a popular dog for commercial breeding purposes, easy to keep and proliferate for producing puppies.