Names may seem odd, but there's a good reason behind them. They have to be original, and they must meet any requirements. In order to compete in the Kentucky Derby, horses must be registered with the racehorse naming-rights authority, The Jockey Club, an organisation that's also in charge of tracking all the thoroughbreds foaled in the United States (including Puerto Rico) and Canada. When it comes to enrolling a horse's name, The Jockey Club has strict guidelines – nearly one third of the 60,000 or so names submitted each year are rejected – for what can and can't be used.For example, the name can't have been used by a previous horse. It can't be longer than 18 letters and can't include initials. It also can't feature a copyrighted term. Horses can’t have the name of a real person unless the horse's owner has written authorisation to use the name. The same rule applies to naming horses after famous people.