As of January 2012, the American Kennel Club recognized 174 different breeds of dog. These breeds are divided into the following seven groups: sporting, hound, working, terrier, toy, non-sporting and herding.
There are, however, many kinds of dogs in the world that are not recognized by any of the major kennel clubs. As of May 2013, the World Canine Organization recognized 339 different breeds of dog, but that number is always growing. All dogs are members of the same species and are capable of inter-breeding, so the number of possible combinations is virtually unlimited. Centuries of dog breeding has led to extraordinary diversity, and breeders are constantly developing new hybrids.