The Golden Retriever is a medium-large gun dog that was bred to retrieve shot waterfowl, such as ducks and upland game birds, during hunting and shooting parties. The name 'retriever' refers to the breed's ability to retrieve shot game undamaged due to their soft mouth. The breed's friendly, gentle temperament means it is unsuited to being a professional guard dog, but its temperament has also made it the third-most popular family dog breed (by registration) in the United States, Golden Retrievers are also noted for their intelligence. The breed ranks fourth in Stanley Coren's The Intelligence of Dogs – following the Border Collie, Poodle, and German Shepherd – as one of the brightest dogs ranked by obedience-command trainability.