A cat bree is an infrasubspecific rank for the classification of domestic cats. A cat is considered to be of a certain cat breed if it is true breeding for the traits that define that breed. Various cat registries around the world record and certify the pedigrees. Only three percent of owned cats belong to a cat breed, and an even smaller percentage of those are suitable as show cats. A registration certificate proves that a cat belongs to a cat breed by showing the cat's pedigree back to at least four generations. The whole concept of cat breeds is a relatively new one. Two hundred years ago there was no such thing, however today there are almost one hundred cat breeds. Varieties of domestic cat can also be identified by characteristics other than breed. See selective breeding for more in-depth detail on purebred animals.