The Labrador Retriever ("Labrador" or "Lab" for short), is one of several kinds of retriever, and is the most popular breed of dog (by registered ownership) in both the United States and the United Kingdom. The breed is exceptionally friendly, intelligent, energetic and good natured, making them excellent companions and working dogs. Labrador Retrievers respond well to praise and positive attention. They are also well known as enjoying water, since historically, they were selectively bred for retrieving in water environments as "gun dogs" and as companions in waterfowl hunting. Labradors are a well-balanced and versatile breed, adaptable to a wide range of functions as well as making very good pets. As a rule they are not excessively prone to territorialism, pining, insecurity, aggression, destructiveness, hypersensitivity, or other difficult traits which sometimes manifest in a variety of breeds, and as the name suggests, they are excellent retrievers. As an extension of this, they instinctively enjoy holding objects and even hands or arms in their mouths, which they can do with great gentleness. Although they will sometimes bark at noise, especially a degree of "alarm barking" when there is noise from unseen sources, labs are not on the whole noisy[18] or territorial, and are often very easygoing and trusting with strangers, and therefore are not very often used as guard dogs. Labradors have a reputation for appetite, and individuals have been described as willing to eat "anything that isn't nailed down."They are also persuasive and persistent in requesting food. For this reason, the Lab owner must carefully control his/her dog's food intake to avoid obesity and its associated health problems. The steady temperament of Labs and their ability to learn make them an ideal breed for search and rescue, detection, and therapy work. Their primary working role continues to be that of a hunting retriever.
Labradors are relatively large with males typically weighing 27 to 36 kg (60 to 80 lb) and females 23 to 32 kg (45 to 70 lb). Their coats are short and smooth, and they possess a straight, powerful tail like that of an otter. The breed tends to shed hair regularly throughout the year. There are three recognised colours for labs: black (a solid black colour), yellow (anything from light cream to gold to fox-red), and chocolate (medium to dark brown).
Information from wikipedia.org