Dogs were kept on a leash by a person known as a slip, who was frequently also the race judge. The slip would release the dogs from their collars at the same time, and they would race towards their owners, who were standing at the opposite end of the track waving towels. Whippet rags were a popular Sunday event in the north and Midlands at the time. There were also international events; in Australia, at a track known as Gurney's Paddock, there were races of more than 300 whippets every Saturday, and three nights a week at the White City track. Eventually, the sport evolved and dogs were divided into four groups: those who hunted rabbits, which was not governed by rules; those who coursed hare, for which a set of rules was established; those trained to the rag; and those trained to chase a mechanical lure in a fashion similar to Greyhound races. Few of the Whippets in any of the four groups were purebred, as maintaining a purebred bloodline was not considered as important as breeding dogs that could win races. Many racing dogs were part-terrier, part-Greyhound, or part-Lurcher. In 1967, the British Whippet Racing Association was established to bring around reform and consistency in race rules and procedures for races involving non-purebred Whippets. A year later, viewing the non-purebred dogs as a threat, the Whippet Club Racing Association was established exclusively for purebred animals. Description Appearance Whippets are a medium-sized dog weighing from . There are two height ranges for Whippets, depending on whether or not the dog is being shown in North America. The Fédération Cynologique Internationale and The Kennel Club both call for heights of for males and for females. Whippets tend to be somewhat larger in the United States and Canada as the American Kennel Club and Canadian Kennel Club standards are larger; for males, and for females. Because colour is considered immaterial in judging Whippets, they come in a wide variety of colours and marking patterns, everything from solid black to solid white, with red, fawn, brindle, blue, or cream. In 2019, The Kennel Club announced it would no longer accept registrations for merle Whippets as it is not a naturally occurring colour in the breed. The coat is short, smooth and close. They are the fastest dog of their weight, capable of achieving speeds of up to , due to their ability