Size
Labradors are relatively large with males typically weighing 65 to 80 pounds and females 55 to 70 pounds. Some labs do become overweight and may weigh significantly more.
Coat and Color
The Lab's coat is fairly short, straight, smooth, and waterproof. They possess a straight, powerful, broad tail that is often likened to an otter's tail. The majority of the characteristics of this breed, with the exception of color, are the result of breeding to produce a working retriever. The breed tends to shed hair twice annually, or regularly throughout the year in temperate climates. Some Labs shed a lot, although individual dogs vary.
Appearance
English Labradors, typically the "show" type, and American Labradors, typically the "working" or "field" types, differ in terms of physical build and mental disposition. Differences in the physical build are the result of specialized breeding. Dogs bred for hunting and field trial work are selected first for working ability, whereas dogs bred to compete for show championships are selected for the characteristics sought by judges in the show ring.
English Labrador Retrievers
English Labradors are medium sized, shorter, and stockier with fuller faces and a slightly calmer nature. They also have a thicker coat and tail. In the head, show Labs tend to have broader heads, better defined stops, and more powerful necks.
American Labrador Retrievers
American Labradors are bred as a longer-legged but lighter built dog. Field Labs have lighter and slightly narrower heads with longer muzzles.