Greyhounds are a member of the larger sight hound family of dogs, a group which includes smaller breeds which were "bred down" from the greyhound (Whippet and Italian Greyhound). Also Basenjis, Salukis, Afghan Hounds, Irish Wolfhounds, Borzois, and others. Sight hounds were bred to hunt by sight, not scent, as do most other dogs. Greyhounds are not only able to scent game, but see clearly at long distances. Racing greyhounds are raised in fenced enclosures on greyhound farms and begin their careers as racers at 18 months of age. They are therefore totally unfamiliar with cars and other hazards puppies usually learn growing up in families/homes. Because of their keen sight, inquisitive natures, and tremendous speed, greyhounds need to be on a leash while being walked or in a fenced area at all times for their own safety (when not in the house). They can reach their top speed of 45 mph in a few, short seconds so using a tie-out is out of the question.