The modern Labrador's ancestors originated on the island of Newfoundland, now part of the province of Newfoundland and Labrador, Canada. The founding breed of the Labrador was the St. John's water dog, a breed that emerged through ad-hoc breedings by early settlers of the island in the 16th century. The forebears of the St. John's Dog are not known, but were likely a random-bred mix of English, Irish, and Portuguese working breeds. The Newfoundland (known then as the Greater Newfoundland) is likely a result of the St. John's Dog breeding with mastiffs brought to the island by the generations of Portuguese fishermen who had been fishing offshore since the 16th century. The smaller short-coated St. John's Dog (also known then as the Lesser Newfoundland) was used for retrieval and pulling in nets from the water. These smaller dogs were the forebears of the Labrador Retriever. The white chest, feet, chin, and muzzle – known as tuxedo markings – characteristic of the St. John's Dog often appear in modern Lab mixes, and will occasionally manifest in Labradors as a small white spot on the chest (known as a medallion) or stray white hairs on the feet or muzzle.
All of those characteristics make the Labrador well-suited to a variety of active families. He’s perfect for homes with rowdy older children, but may be a little rambunctious around toddlers, especially as a puppy or young dog. Singles and couples who love the outdoors also match up well with this breed, and his size and even temperament make the Labrador a great companion for active seniors who love to walk and would appreciate a dog who looks intimidating, even if he is more of a lover than a fighter.
While individual dogs may vary, in general show-bred Labradors are heavier built, slightly shorter-bodied, and have a thicker coat and tail. Field Labradors are generally longer-legged, lighter, and more lithe in build, making them agile. In the head, show Labradors tend to have broader heads, better defined stops, and more powerful necks, while field Labradors have lighter and slightly narrower heads with longer muzzles. Field-bred Labradors are commonly higher energy and more high-strung compared to the Labrador bred for conformation showing while conformation breeds are calmer in energy, and as a consequence may be more suited to working relationships than being a "family pet". Some breeders, especially those specialising in the field type, feel that breed shows do not adequately recognise their type of dog, leading to occasional debate regarding officially splitting the breed into subtypes.
Obviously, Labradors have a number of endearing traits or they would not be so popular. They are intelligent and fairly easy to train, partly from their desire to work with people. They are "easy keepers" and can become overweight if they are not exercised and food portions adjusted as needed. Labs are excellent family dogs because they do want to be with people and many do not do well as kennel dogs.
It has been shown that out of all dog breeds, it is the Labrador Retriever that is most likely to be obese. In a 2016 published study it was shown that out of 310 Labradors, most were missing all or parts of the POMC gene. This gene plays a part in appetite regulation as well as indication of the amount of one's stored fat. The study concluded that the absence of that gene had a significant impact on Labrador weight and appetite. The POMC gene mutation is present in only one other breed – the Flat-Coated Retriever.