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.
Labradors are relatively large, with males typically weighing 29 to 41 kg (64 to 90 lb) and females 25 to 32 kg (55 to 71 lb). Labradors weighing close to or over 100 lb (45 kg) are considered obese or having a major fault under American Kennel Club standards, although some Labradors weigh significantly more. The majority of the characteristics of this breed, with the exception of colour, are the result of breeding to produce a working retriever.
As with some other breeds, the Conformation (typically "English", "show" or "bench") and the Field (typically "American" or "working") lines differ, although both lines are bred in both countries. In general, however, Conformation Labradors tend to be bred as medium-sized dogs, shorter and stockier with fuller faces and a slightly calmer nature than their Field counterparts, which are often bred as taller, lighter-framed dogs, with slightly less broad faces and a slightly longer nose; however Field Labradors should still be proportional and fit within AKC standards. With field Labradors, excessively long noses, thin heads, long legs and lanky frames are not considered standard. These two types are informal and not codified or standardized; no distinction is made by the AKC or other kennel clubs, but the two types come from different breeding lines. Australian stock also exists; though not seen in the west, they are common in Asia.
Labradors are a relatively large breed. They should be as long from the withers to the base of the tail as they are from the floor to the withers. Males should stand 22.5 to 24.5 inches (57 to 62 cm) tall at the withers and weigh 65 to 80 lb (29 to 36 kg). Females should stand 21.5 to 23.5 inches (55 to 60 cm) and weigh 55 to 70 lb (25 to 32 kg). By comparison under UK Kennel Club standards, height should be 22 to 22.5 inches (56 to 57 cm) for males, and 21.5 to 22 inches (55 to 56 cm) for females
Labrador Retrievers are registered in three colours: black (a solid black colour), yellow (anything from light cream to "fox-red"), and chocolate (medium to dark brown). Some Labrador retrievers can have markings such as white patches on their chest and other areas, but most commonly they are one solid color.
The AKC describes the Labrador's temperament as a kind, outgoing
and tractable nature. Labradors' sense of smell allows them to hone
in on almost any scent and follow the path of its origin. They generally
stay on the scent until they find it. Labradors instinctively enjoy
holding objects and even hands or arms in their mouths, which they
can do with great gentleness (a Labrador can carry an egg in its
mouth without breaking it). They are also known to have a very soft
feel to the mouth, as a result of being bred to retrieve game such
as waterfowl. They are prone to chewing objects (though they can
be trained out of this behavior). The Labrador Retriever's coat
repels water to some extent, thus facilitating the extensive use
of the dog in waterfowl hunting.
Labradors have a reputation as a very even-tempered breed and an excellent family dog. This includes a good reputation with children of all ages and other animals.
Labradors like to eat and without adequate exercise, can become obese. Laziness also contributes to this. Obesity is a serious condition, and can be considered the number one nutritional problem with dogs.
A study shows that at least 25% of dogs in the United States are overweight. Therefore Labradors must be properly exercised and stimulated. A healthy Labrador can do swimming wind sprints for two hours, and should keep a very slight hourglass waist and be fit and light, rather than fat or heavy-set. Obesity can exacerbate conditions such as hip dysplasia and joint problems, and can lead to secondary diseases, including diabetes. Osteoarthritis is common in older, especially overweight, Labradors. A 14 year study covering 48 dogs by food manufacturer Purina showed that Labradors fed to maintain a lean body shape outlived those fed freely, by around two years, emphasizing the importance of not over-feeding. Labradors should be walked twice a day for at least half an hour