The domestic cat is a mammal of the species Felis silvestris catus that has for many thousands of years been a constant companion of humans. Originally domesticated in ancient times, cats have been much valued for their ability to catch mice and other vermin, and for their loving and loyal relationship with their human masters. Nocturnal by nature, cats living outside of human society, known as feral cats, invariably revert to a night-time existence.
There is some debate as to the original time at which cats were domesticated, as mummified cats have been found in Cyprus dating back to at least 6,000 B.C. according to secular dating. Cats are strictly carnivorous, so they do not usually eat carbohydrate-heavy human foods like grains and fruits; they are thus a natural companion for humans. Some evidence has found that cat ownership has health benefits, especially in the elderly.
There are over 50 domestic cat breeds, among them the Abyssinian, the American Bobtail, the American Shorthair, the Balinese, the British Shorthair, the Burmese, the Cornish Rex, the Egyptian Mau, the Manx, the Nebelung, Norwegian Forest Cat, the Persian, the Russian Blue, the Siamese and the Turkish Angora. Cat breeds differ widely in terms of coloration, amount and location of body hair, and size. As with human races, there is no evidence that cat breeds are monophyletic groups; they are grouped based largely on a small number of physical characteristics.