According to Wilkipedia,
"The Labrador Retriever (also Labrador or Lab for short), is one of several kinds of retriever, a type of gun dog. The Labrador is widely considered the most popular breed of dog (by registered ownership) in the world, and is by a large margin the most popular breed by registration in the United States (since 1991), the United Kingdom, and several other countries.[1] It is also the most popular breed of assistance dog in the United States, Australia, and many other countries, as well as being widely used by police and other official bodies for their detection and working abilities.[2]
Historically, Labrador Retrievers were bred for retrieving in water environments, and as companions in waterfowl hunting. As a breed, this is still evident in their near-universal love of water. They are exceptionally affable, gentle, intelligent, energetic and good natured,[1][2][3] making them both excellent companions and working dogs. Although somewhat boisterous if untrained, Labrador Retrievers respond well to praise and positive attention, and are considerably "food and fun" oriented. With training, the Lab is one of the most dependable,[4] obedient[1] and multi-talented[2] breeds in the world."