The first St. John's water dogs, bred by European immigrants in Newfoundland, were brought to Britain by ships travelling between Canada and Poole in Dorset in the 1830s, which is when the Labrador breed originally appeared. The Labrador Retriever was eventually developed by crossing these with British hunting dogs. Early supporters of the organisation included Sir John Scott, the Earl of Malmesbury, the Duke of Buccleuch, and the Earl of Home. The Labrador has been mistaken for the much larger Newfoundland and the Lesser Newfoundland by early writers, including Charles St. John, who even called the Lesser Newfoundland the Newfoundland.

The first Labrador was described by Colonel Peter Hawker as being smaller than an English Pointer, more frequently black than other hues, and having a long head.

Labradors come in a wide range of variations. Based on the American Kennel Club standard, the following traits are typical of this breed's American conformation show bred (bench-bred) lines. 2] There are noticeable variances between UK and US standards.

Labradors are a medium-sized breed of dog. The distance from the floor to the withers should equal the distance from the withers to the base of the tail. The AKC standard specifies a weight range of 25-36 kg (55-80 lb) for dogs and 25-32 kg

(55-70 Ib) for hens. [2] The AKC sets height standards for dogs that range from 55 to 62 centimetres (21.5 to 24.5 in) and for cats that range from 55 to 60 centimetres (21.5 to 23.5 in).A Labrador is expected to have a lifespan of 10-12 years.
It is a healthy breed with relatively few major problems. Major health and wellness issues include hereditary diseases and obesity (most are missing all or part of the  POMC gene, which regulates appetite). 
A study by the Royal Veterinary College  and a study by the University of Sydney concluded that chocolate Labradors have a shorter  life expectancy than other Labradors (by about 10 percent) and are more likely to suffer from certain health problems. 24] 
Labradors are somewhat prone to hip and elbow dysplasia[25], especially in larger dogs.[26] Eye diseases can include progressive retinal atrophy, cataracts, corneal dystrophy [25] and retinal dysplasia [27]. They can suffer from stress-induced collapse, which causes hyperthermia, weakness, collapse and disorientation after a short exercise[28], or from obesity, which in some cases can be partially or completely due to the absence of  the proopiomelanocortin gene.