Labrador Retrievers are sporting dogs, bred to return small game to hunters without running off and eating it themselves. They have "soft" mouths so they won't damage the game. They will leap eagerly into water to retrieve birds and other things. Labs have webbed toes to help them swim as well as a thick undercoat of hair for better insulation against the cold. They are very affectionate, friendly, and like to be around people. Labs come in varying shades of three colors: black, yellow, and chocolate, chocolate being the least common.
There are two "types" of labs (that I know of), show, and field or working labs. Show labs are most often seen in the ring, they are heavier through the neck and tend to have a wider head. Field labs, of which Rocket is one, are slimmer with a narrower head, hypothetically, this helps with their agility.
Labs are voracious eaters and often act as though they are starving. Whether this leads to the owner over feeding them or the fact that they don't get enough exercise, fat labs can be seen everywhere. Since labs are prone to hip displaysia being over weight is not good. The average weight of an adult male is 70-75 pounds; a female adult is 60-65 pounds. Rocket tipped the scales recently at 77 and the vet said "no more".
Because labs love to eat fast, they seem more prone to a problem called bloat. This is when the stomach rotates between the esophagus and the small intestine, cutting off it's blood supply and is deadly within an hour or so unless immediately corrected by surgery. Consequently it is deemed better to feed a lab 2 smaller meals twice per day than one large meal per day.
*I am not a recognized medical authority, these facts are my own knowledge and should not be taken as the final word.