Spaniels were first mentioned in the 14th century by Gaston III of Foix-Béarn in his work the Livre de Chasse. The "Cocking" or "Cocker Spaniel" was first used to refer to a type of field or land spaniel in the 19th century. Prior to 1901, Cocker Spaniels were only separated from Field Spaniels and Springer Spaniels by weight. Two dogs are considered to be the foundation sires of both modern breeds, the English variety are descended from Ch. Obo, while the American breed follows in the footsteps of Obo's son, Ch. Obo II. In America, the English variety was recognized as separate from the native breed in 1946; in the UK, the American type was recognized as a separate breed in 1970. In addition, there is a second strain of English Cocker Spaniel, a working strain which is not bred to a standard but by working ability.
Both breeds share similar coat colors and health issues with a few exceptions.
Called simply Cocker Spaniel in the UK, this is the breed that was originally recognized by The Kennel Club in 1892. The American Kennel Club recognized the English Cocker Spaniel as a separate breed in 1946.
The size of the English Cocker Spaniel according to The Kennel Club is 15.5–16 inches (39–41 cm) at the withers for males, and 15–15.5 inches (38–39 cm) for females. The weight of a show dog should be 28–32 pounds (13–15 kg).
The English Cocker Spaniel is the most successful breed at the most popular dog show in the UK, Crufts, with seven best-in-show wins since the prize was first awarded in 1928. This was mostly due to the success of dog breeder H.S. Lloyd's Ware Kennel, who won best-in-show on six occasions between 1930–1950. They are the second most popular dog breed in the UK according to statistics released by The Kennel Club with 22,211 registrations in 2009, beaten only by the Labrador Retriever with 40,943. In third place was the English Springer Spaniel with 12,700 Their popularity has increased steadily since 1999 in the United States when they were ranked 76th in registrations by the American Kennel Club, to 2009 when they were ranked 66th
There is a split between the show strains and working strains in the UK. While the show strain is bred to the conformation standard, the working strain is bred for working ability and as such several physical differences have appeared. Working type dogs tend to be larger with flatter heads and shorter ears. The coat also tends to be finer than the show variety and have less feathering